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To elucidate the normal development and growth of Mongolian gerbils, the timing and sequence of the appearance of ossification centres within foetuses were investigated. Average foetus body weight and tail length on the 15th day of pregnancy were found to be 0.042 g and 6.2 mm, respectively. For the 25th day of pregnancy, these measurements were 2.601 g and 29.4 mm, respectively. The body weight and tail length of foetuses increased significantly from the 20th day of pregnancy. Also, the first ossification centre of Mongolian gerbil foetuses appeared in the clavicle at the 17th day of pregnancy. The order in which ossification centres appeared in Mongolian gerbils resembles the pattern for rats and mice, except in some areas of the skull. Except for the clavicle, in which ossification centres appeared rather early, most ossification centres appeared in the last quarter of pregnancy. These results suggest that Mongolian gerbil foetal development is near completion by the last gestational stage. Also, ossification centres appear sooner in the skull and nasal bones than in other rodents.

The susceptibility to Leptospira interrogans serovar copenhageni in Mongolian gerbils treated with 10 micrograms of serum thymic factor (FTS) 1 day before infection was examined. Susceptibility of gerbils treated 5 times with 10 micrograms of FTS was also investigated. Mortality of FTS-treated gerbils was significantly lower than that of controls when small challenge doses were used. To analyse the FTS-induced resistance to leptospiral infection, natural killer (NK) cell activity and macrophage activity were studied. Macrophage activity was unaltered but NK cell activity was enhanced in FTS-treated gerbils, with or without leptospiral infection. Since no side-effects of FTS were observed, this compound should be considered for the treatment of leptospirosis.

In Mongolian gerbil, morphological changes with age in the content of endocrine cells in the pancreatic islets were analyzed and their relation evaluated by an oral glucose tolerance test. The glucose level 2 hours after glucose administration was 125 +/- 5 mg./d1 in the young group and 103 +/- 4 mg./d1 in the old group. In the dorsal portion, B cells were mainly observed in the central area of the islets, surrounded by circular layers of A cells in the peripheral area. Between the A cells and B cells, D cells were scattered or present in layers. A few PP cells were present in the peripheral area of the islets. In the ventral portion, only a few A cells were observed in the peripheral area of the islets, and B cells were surrounded by PP cells. Secretory granules of A cells generally had an electron-dense spherical core in the limiting membrane. The halo between the limiting membrane and core in A cells was narrower than that in B cells. Secretory granules of B cells were larger than those in A cells, and the core was less electron-dense, and the halo was wider. Secretory granules of D cells were similar in size to those of A cells; the core showed low electron density, and the halo was very narrow. Granules of PP cells resembled those of A cells, but the electron density of the core was slightly lower. The gerbils showed changes in glucose tolerance, the size of the pancreatic islets, the percentage of B cells, and of A cells in the dorsal portion with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemiluminescence studies on superoxide generation by phagosomes using opsonized zymosan showed the highest fluorescence in murine splenic macrophages among four different kinds of splenic or peritoneal macrophages from mice or gerbils. Murine splenic macrophages phagocytized two to three times more latex particles than gerbil splenic macrophages, but peritoneal macrophages did not show a significant difference in phagocytic activity between mice and gerbils. Phagocytosis by macrophages was determined by a technique based on measurement of the release of hydrogen peroxide and myeloperoxidase from phagosomes using microspheres conjugated with 3-(p-hydroxyphenyl) propionic acid (HPPA-MS). HPPA is a substrate of lysosomal myeloperoxidase. The fluorescence of HPPA-HPPA-MS produced by phagocytized HPPA-MS was measured with an immunoreaction analysis system (IMRAS), and the enzyme activities of the four different kinds of peritoneal or splenic macrophages from mice and gerbils were compared. All four kinds of macrophages produced HPPA-HPPA-MS in their phagosomes during phagocytosis and murine splenic macrophages showed the highest level of enzyme activity.

Atrial natriuretic peptide (ANP) levels in cardiocytes and plasma were examined by using immunohistochemistry, electron microscopy, and radioimmunoassay in non-obese diabetic mice (NOD). Cardiocyte ANP mRNA expression was measured by the polymerase chain reaction method. ANP immunoreactivity in the auricular cardiocytes was more prominent in hyperglycemic mice (NOD-h) than in normoglycemic mice (NOD-n). Ultrastructural examination showed that auricular cardiocytes of the NOD-h group contained more cytoplasmic granules than cells of the NOD-n group. Ultrastructural morphometry indicated that the number of granules per auricular cardiocyte was significantly larger in the NOD-h group than in the NOD-n group (P less than 0.01), whereas the granule diameter was significantly smaller in the NOD-h group (P less than 0.01). Radioimmunoassay showed that ANP levels in the NOD-h auricular cardiocytes were significantly higher than those in the NOD-n cardiocytes (P less than 0.01); the opposite was true in plasma. Cardiocyte ANP mRNA expression was lower in the NOD-h group than in the NOD-n group.

During pre-and postnatal development, the atrial natriuretic peptide (ANP)-granules in the right and left auricular cardiocytes of Syrian hamsters were studied immunohistochemically and by transmission electron microscopy. Moreover, the number and diameter of ANP-granules in the cardiocytes were analyzed by ultrastructural morphometry. Immunohistochemically, the ANP immunoreactivity was located primarily in the perinuclear region in auricular cardiocytes of the neonatal group, but was located diffusely in the cells of the fetal group. At the 15th day of gestation, the immunoreactivity was stronger than at the 13th day of gestation. The ANP immunoreactivity observed in the cardiocytes of the newborn was weaker than in the fetal group. During the postnatal growth period, the immunoreactivity became gradually stronger. Ultrastructurally, ANP-granules in the fetal cardiocytes were scattered in the cytoplasm with immature organelles. During the postnatal growth period, the granules were predominantly located in the perinuclear region associated with the Golgi apparatus. By ultrastructural morphometry, the number of granules in the right auricular cardiocytes was significantly greater than in the left auricular cardiocytes in all groups examined. In the newborn, the number of granules was significantly less than that in the fetal group. During the postnatal growth period, the granule number of cardiocytes significantly increased. There was no significant difference between the granule number of 10-day-old neonates and of 90-day-old neonates. During the postnatal period, the granule diameter in both auricles was significantly greater than in the fetal group. The granule size was not significantly different between the right auricular cardiocytes and the left ones in all groups examined. It is suggested that a large amount of ANP-granules is secreted at the perinatal period, resulting in granule depletion in both auricular cardiocytes.

We studied the effects of immune sera, an antibiotic, and a corticosteroid used alone or in combination on leptospira infection in Mongolian gerbils (Meriones unguiculatus). The results suggest that the combined used of immune serum and corticosteroid (pledonizoron: PZ) inhibits the effects of serum and the marked effects of antibiotic (procaine penicillin-G: PC-G) on leptospirosis. PZ had no effects and rather shortened the survival period. PZ did not affect the effects of PC-G when used in combination. These results suggest that treatment of leptospirosis with corticosteroids requires special caution.

On day 13 of gestation in Mongolian gerbil fetuses, the mesonephric (Wolffian) duct was already visible. On day 14, the anlage of the paramesonephric (Mullerian) duct was first observed close to the mesonephric duct in both sexes at the cranial part of the mesonephros. Thereafter, the paramesonephric duct grew caudally in parallel with the mesonephric duct. On day 19, the duct reached the urogenital sinus. At this stage, the anogenital distance was significantly longer in male than in female. Also in male, the mesonephric duct was increased and the paramesonephric duct was decreased in diameter compared with those in female. These suggest that both testosterone and anti-Mullerian hormone are produced in fetal Mongolian gerbils at least before day 19 of gestation.

A cell line was established from a Mongolian gerbil's (Meriones unguiculatus) homotransplantable malignant melanoma. Ascitic tumor cells detected in a gerbil when transplanted intraperitoneally were adapted to culture. In primary culture, cells were divided into 2 types, multipolar and polygonal cells. Cell masses which adhered to polygonal cells were observed after the 6th passage. The adhering cells were removed and transferred into another flasks. The cells showed multipolar and possessed projections. Then after, the cells increased in number vigorously and formed acinous structures. At early passages, abundant melanin granules in some of the cells were demonstrated by light and electron microscopical observations. Most of the cells were positive by DOPA reaction. Melanin pigments were gradually decreased through the 20th to 30th passage and most of cells became amelanotic. The doubling time of the cell line was 32 hr. Chromosome number of the cell line ranged from 68 to 82. Whitish tumors were produced in the abdominal cavity within 30 days when intraperitoneally inoculated the cells to gerbils. This cell line, designated as MGM-A, has been subcultured for more than 100 passages during 2 years.

Gerbils were inoculated with reovirus type 3 (Abney strain), and the pancreas, brain and other organs histopathologically evaluated. Male Mongolian gerbils (Meriones unguiculatus) aged 5-10 days (newborn, 9 animals), 4 weeks (juvenile, 5 animals), and 12 weeks (adult, 5 animals) were used. Gerbils inoculated intraperitoneally with the virus were sacrificed 3, 5, 7, or 10 days later. Tissues were observed by light and electron microscopy. The pancreas of newborns showed inflammatory edema with infiltrates of neutrophilis and mononuclear round cells, degranulation of acinar cells and dissociation of lobules and acini with necrosis at 3 days or later after inoculation but not degeneration of pancreatic islets. Brains of newborns had necrosis of neurons and aggregation of microglial cells in the brain stem and cerebral hemisphere. Azurophilic inclusion bodies were seen in the cytoplasm of some neurons. In electron micrographs, virus particles (60-80 nm in diameter) were observed around the nucleus of neurons in the brain stem. No changes were observed in the juvenile and adult gerbils.

The atrial natriuretic peptide (ANP)-granules of right auricular cardiocytes were studied in aging Mongolian gerbils by immunohistochemistry and transmission electron microscopy, and analyzed by ultrastructural morphometry. Immunohistochemically, the ANP immunoreactions were weaker in 3 and 4-year-old animals than in 90-day-old, 1- and 2-year-old animals. There was no difference in the reaction among 90-day-old, 1 and 2-year-old animals, or between 3 and 4-year-old animals. Ultrastructurally, the morphological features in 1 and 2-year-old animals were similar to those of 90-day-old animals, but distinct in 3 and 4-year old animals by the presence of a few lysosomal structures in the cell. By ultrastructural morphometry, number and diameter of ANP-granules of 3 and 4-year-old animals were significantly smaller than those in the 90-day-old, 1 and 2-year-old. There was no significant difference in number and diameter among the 90-day-old, 1 and 2-year-old, or between the 3 and 4-year-old.

In the pig, cattle and horse, the right and left atria and ventricles were examined by immunohistochemistry, and the right atrial and auricular cardiocytes were studied by transmission electron microscopy. Moreover, ANP-granules in the cardiocytes were analyzed by ultrastructural morphometry. Immunohistochemically, the most intensely ANP-reacted cardiocytes were localized in the right auricle, particularly more prominent in the pig and cattle than in the horse. Ultrastructurally, ANP-granules were located principally in the perinuclear region associated with the Golgi apparatus and throughout the sarcoplasmic layers. They were classified into 2 types, A and B. A-granule had a conspicuous electron-dense core enveloped by a membrane. B-granule had a fibrillogranular core enveloped by an indistinct membrane. By TEM equipped with a goniometer stage, a part of the limiting membrane of B-granules became visible as the stage tilt progressed. By ultrastructural morphometry, the number of each type of granules was significantly greater in the pig and cattle than in the horse. In the pig and cattle, the total number of both types of granules in the auricular cardiocytes was significantly greater than that in the atrial ones. The diameter of each type of granules was significantly larger in the pig and cattle than in the horse. The diameter of A-granules was significantly larger than that of B-granules.

Mongolian gerbils, Meriones unguiculatus, were shown to be highly susceptible to Leptospira interrogans serovars such as icterohaemorrhagiae, copenhageni, canicola, autumnalis, javanica, pyrogenes and hebdomadis as compared to guinea pigs and hamsters. Mortality with signs of haemorrhage and jaundice was recorded in all experimental rodents after intraperitoneal inoculation with all strains of the serovars indicated. However, Mongolian gerbils were comparatively susceptible to strains which were of low virulence to guinea pigs and hamsters. Use of leptospiral vaccination proved effective in protecting the animals against inoculum challenges. The Mongolian gerbil is a species that may be selectively and preferentially useful for assays on the protective effects of leptospiral vaccination.

The atrioventricular (AV) conducting system of the heart was histologically investigated in 14 species in 9 orders of aves. The main part of the AV conducting system in aves was fundamentally similar to that in mammals, but the avian AV bundle was longer than the mammalian one and its left and right limbs had no branches crossing the ventricular cavities. In the avian heart, the accessory part of the AV conducting system was well developed. It consisted of the right AV Purkinje ring, which originated from the AV node, and the recurrent branch, which emanated from thd AV bundle. In general, the former encircled the right AV orifice and the latter encircled the aortic root, together forming an 8-shaped loop. However, the degree of development of the accessory part varied among avian species, hence allowing six types of the accessory part to be distinguished.

本研究の目的は, ニホンイノシシの年令と性の判定基準を作成することである. 材料として, 飼育イノシシ8例と丹波産野生イノシシ122例の頭蓋標本を用い, 歯牙の肉眼および組織学的観察をおこなった. 結果は以下の5点に要約される. 1. 歯牙の萌出と咬耗の程度によって, 12月に捕獲された89例の野生イノシシ頭蓋標本は5年令群に区分された. 2. 下顎第一後臼歯の歯根岐部の象牙およびセメント質に形成ざれる年輪によって, 上記の5年令群は7力月令およびそれに1年ずつ加算した年令に対応することが確認された. 3. 年輪を構成する広帯と薄帯のうち,後者のCa含量が高いことが認められた. 4. 年令が明らかな8例の飼育イノシシ頭蓋標本における歯牙の萌出は, 野生イノシシの歯牙の萌出と一致するものであった. 5. 解剖所見によって性別が明らかな122例の頭蓋標本を用いて性判別の基準を求めた. その結果, 下顎犬歯の冠部と頚部の計測によって, Age class II (生後19～20カ月令)以降の頭蓋標本は, 100%の的中率で性の判別が可能となった. また下顎体犬歯部のX線撮影によって, 生後6力月令の性判別ができることが明らかになった.

In the golden hamster (Mesocricetus auratus) the gestation period and the loculus size of the gravid uterus from day 6 to day 15.5 (parturition) of gestation as well as the weight, width (umbilcus-black) and lenght (crown-rump) of the embryos from day 9 to the parturition were measured. The results obtained were as follows: 1. The gestation period of the golden hamster was 15 days and 15 +/- 3 hours post coitum. 2. The average values of the length (in the direction of uterine long axis) and width (mesome-trial-antimesometrial axis) in the loculus of the gravid uterus were 0.39 cm and 0.56 cm at 6 days, and 2.42 cm and 1.74 cm at 15.5 days (partiurition), respectively. 3. The average values of the crown-rump measurements, width (umblicus-back) and weight in the hamster embryos were 0.42 cm, 0.24 cm and 0.026 g at 9 days, and 2.40 cm, 1.39 cm and 2.272 g at 15.5 days (parturition), respectively. 4. The loculus size of the gravid uterus, the crown-rump measurements and width (umblicus-back) of the embryos in the period from day 13 to day 14 of gestation were markedly increased in comparison with any other period, and the weight increase of the embryos occurred rapidly from day 13 of gestation. 5. The shape of the loculus during the gestation was ovoid (mesometrial-antimesometrial axis) until the end of 10 days converged to the spherical form and thereafter changed gradually to the ovoid from in the direction of uterine long axis contraly to the previous days.

In order to clarify the relationship between three types of Indonesian native pigs (Bali, Batak of North Sumatra, and Toraja of South Sulawesi) and seven populations of Asian wild boars (Honshu, Kyushu, and Amami of Japan, Taiwan, Sumatra and Sulawesi of Indonesia, and Thai), the multivariate craniometric comparisons using 10 mandibular measurements were carried out in the present study. The results are summarized as follows: (1) Seven populations of Asian wild boars were separated into three groups by sizes: small, medium, and large, based on the discrimination by the first principal component acceptable as a size vector. The second principal component, acceptable as a shape vector, also contributed some towards the discrimination of the small-sized group from the other groups. (2) There is a complete overlapping of the principal component chart between the Batak native pigs and Toraja native pigs, both of which are short-eared. These two pigs occupy the intermediate situation between the small-sized wild boar and the medium-sized one, when they are projected into the axis of the first component. On the other hand, when they are projected into the axis of the second component, these two pigs fell in the medium-sized group of the wild boar. The Bali native pig, which is a Hainun type of the native pig, is probably to be separated both from the wild boars and from other native pigs. (3) The proportion of the ramus of the mandible to the body of the mandible seems to be an important discriminator in its shape, since the eigenvectors of measurements belonging to the ramus of the mandible show negative values, whereas those belonging to the body of the mandible show positive ones, in the second component.

Ultrastructural changes of the cells forming germinal centers were examined in the chick spleen after intravenous injection of sheep red blood cells. The germinal center was formed by a cluster of large lymphoid cells and a septum of flattened reticular cells. The large lymphoid cell was characterized by numerous polysomes and a large euchromatic nucleus with a prominent nucleolus. In the developing germinal center the large lymphoid cells proliferated and became smaller in size. After the peak of development of the center they were gradually atrophied and finally became degenerative to exhibit pyknotic nuclei, condensed cytoplasm, some vacuoles and many cytoplasmic processes. From the formation of the germinal center through its degeneration, the transformation of lymphoid cells into plasma cells did not occur within the center. Plasma cells were appeared in the red pulp prior to the germinal center formation, and then they proliferated to aggregate around a periarterial lymphatic sheath.

The external genitalia in bovine fetuses were studied macroscopically, with special reference to the formation of the labia and the sexual differentiation. The age of fetuses was expressed in crown-rump length (CRL). The female urogenital fold budding on either side of the genital tubercle gradually approached the tip of the genital tubercle by the 33-cm stage and then began to enclose it with the companion fold on the other side, thus forming the labium pudendi which is equivalent to the labium minus pudendi of the human. The genital swellings, which are known to become the labia majora in the human, did not take part in the formation of the labia. They completely disappeared at the sites cranial to the genital tubercle by the l0-cm stage. The sex difference in differentiation of the external genitalia was first observed at the 2.7-cm stage, at which time in the male, the urogenital orifice and the anogenital raphe appeared at the sites caudal to the genital tubercle; in the female at the 2.9-cm stage, both structures were still not observable. The anogenital distance became clearly longer in male than in female, after 3.6-3.9-cm stages.

First, the hamster nasal turbinates were nominated as nasoturbinate, maxil-loturbinate, endoturbinates I, II, II", III and IV, and ectoturbinates 1, 2 and 3. Next, inorder to clarify the course of their development, animals from 11.0 days of gestation to149 days after birth were examined. As a result, nasoturbinate, maxilloturbinate, andendoturbinates I, II and III had already been formed by 11.0 days of gestation. Endo-turbinate II" appeared at 12.0 days, endoturbinate IV and ectoturbinate l at 12.5 days, and ectoturbinates 2 and 3 at 13.0 days. Endoturbinate IV and ectoturbinate 2 developedin the form of epithelial ridge, and ectoturbinates l and 3 in the form of subepithelialmesenchymal ridge. Endoturbinate II" was formed secondarily from endoturbinate II byseparation. Further, the course of development of each nasal turbinate was schematicallysummarized. The surface area of each nasal turbinate was measured in various growthstages. Based on these embryological findings, discussion was made on the nomenclatureof the nasal turbinates.

妊娠20日に母ラットの卵巣を除去後, 妊娠22日に剖検し, または妊娠20日の胎仔にβ-estradiol(0.02mg)を皮下注射し, 妊娠22日と生後1日に剖検して Leydig 細胞の総体積およびその組織像を検索したところ, estradial は出生前の Leydig 細胞の発達と出生後の萎縮に影響しなかった.

Renal juxtaglomerul;tr cell granulation in some mammals was demonstratedby Bowies staining method. Hartroft and llatrofts index was applied to different speciesin one trial. It was high in the mouse and rat, and low in the hamster. These resttlts werecorrelative with those reported by Capelli who measured the renal renin content in sonnemammalian species. In the horse, cow, sheep and guinea pig large grantnles, whiclt werestained by Bowies method, were observed near the glomerular arteriole. Then in themouse these granules were studied by electron microscope. It was observed that large cellswhich contained many heterogenous lysosomes were present in the outer layer of theepithelium of the glomerular capsttle. This observation suggested that the large granulesseen by light microscope might not be juxtaglomerular cell granules, bttt ordinarylysosomes.

Comparative histologic observations were made of the sinuatrial nodes of avian hearts from a short-tailed shearwater (Puffinus tenuirostris), a black-crowned night heron (Nycticorax nycticorax), two ducks (Anas platyrhycha domestica), eight Japanese quails (Coturnix coturnix Japonica), a pigeon (Columba livia domestica), a macaw (Ara macao), three budgerigars (Melopsittacus undulatus) and a jungle crow (Corvus macrorhynchos). The node lies between the right atrial myocardium and epicardium at the right caudal region of the orifice of right anterior vena cava, where the right and left sinuatrial valves come close each and fuse with the right atrial wall. The sinuatrial node is well developed in the duck, black-crowned night heron and budgerigar and enters into the both sinuatrial valves and, in the budgerigar, further into the sinus septum. In the duck and black-crowned night heron, the node is composed of two types of cells; the one is atrial muscle-like cells and the other has morphologic characteristics intermediate between atrial muscle fiber and the Purkinje fiber. The node cells of the budgerigar are of the intermediate cells, while the nodal cells in the jungle crow, macaw, short-tailed shearwater, pigeon and Japanese quail are totally atrial muscle-like cells. The nodal cells of these birds are continuous with the adjacent ordinary cardiac muscle fibers and subendocardial Purkinje fibers of the right atrium, but do not reach to the atrioventricular node. There is an extensive network of Purkinje fibers beneath the endocardium and around arteries in both atrial walls, though not as far as to the atrioventricular node, nor to the ventricle.

Morphological features of the vomeronasal organ in the golden hamster were examined by light and electron microscopy. This organ consisted of a 7 mm long tubular structure situated bilaterally in the anteroventral nasal septum and enclosed completely by a bony capsule. Posteriorly it ended blindly, whereas anteriorly it communicated with the nasal cavity through an orifice at its rostral end. The sensory epithelium lining the medial wall of the lumen of this organ showed a cell configuration similar to that of the olfactory epithelium except the basal cells. Free surface of the sensory cells in the sensory epithelium was covered with structures intermediate between cilia and microvilli. Capillaries often penetrated into the sensory epithelium, and the vomeronasal nerve observed under the sensory epithelium consisted of nonmyelinated nerve fibers. The respiratory epithelium lining the lateral wall of the lumen of this organ was typically ciliated and pseudostratified, devoid of goblet cells. Mucous and serous acini of Jacobson's glands were distributed on the dorsolateral and ventromedial sides of the lumen. The glands were PAS-positive, different from alcian blue-positive olfactory glands of Bowman. Myelinated and nonmyelinated nerve fibers were often distributed among the acini.

The proventriculus of duck is lacking in the V. proventricularis dextra and V. proventriculolienalis both of which are present in the chicken. In it the V. lienalis empties directly into the V. portae hepatis dextra. Therefore, most of the blood from the proventriculus of duck is drained by the well-developed V. proventricularis cranialis and empties into the V. cava cranialis sinistra without showing any morphological relation to the portal vein. A small amount of the remaining venous blood is drained by the portal vein after passing through the V. proventricularis sinistra; that is, most of the venous blood in the proventriculus of duck empties into the systemic circulation. In the wall of the proventriculus of duck there is a dense venous network formed by anastomosis between V. proventricularis cranialis and V. proventricularis sinistra. The systemic circulation is connected directly with the portal circulation by this anastomosis. Such a close connection between the systemic and portal circulations and the distribution of venous blood from the proventriculus appear to be a noticeable problem in birds in association with phylogenetics and food habits. Although the principle for the terminology of the venous system in the avian proventriculus was proposed by the authors, further experiments and discussion will be required for a uniformity of the nomecnlature in the future.

The histological development of the paracloacal vascular body was observed in the male embryo of muscovy duck. On the 14th day of incubation, the primordium of the paracloacal vascular body was first recognized as an oval mass of mesenchymal cells containing a few blood capillaries and which lay lateral to the urodeum. The well-developed blood vascular system as well as the arterioles and venules was distinguished on the 16th day. The capillary cord and the peripheral lymphatic space partly appeared on the 18th day. After this stage the peripheral lymphatic space was gradually formed around the whole parenchyma of the body, and the internal lymphatic space, the trabecula and the capsule were also developed simultaneously. All of the main components of the paracloacal vascular body thus appeared by the 24th day of incubation. On the other hand, the lymphatic space of the fibrolymphatic body occurred from the peripheral lymphatic space of the paracloacal vascular body on the 19th day. Typical reticular lymphatic spaces were formed in the fibrolymphatic body on the 24th day.

食虫目トガリネズミ科に属するリュウキュウジャコウネズミの腸管の形態学的特徴を体重のほぼ等しい齧歯類のマウス・ハムスターのそれらと光学顕微鏡, 走査型および透過型電子顕微鏡を用いて比較検討した. ジャコウネズミの腸管の特微として, まずその長さが非常に短かくまた盲腸の欠如している事があげられる. このため小腸と大腸の境界は不明瞭である. 絨毛は小腸ばかりでなく, 大腸に相当する部位にも存在する. これらの絨毛は齧歯類とは異なり, 表面の小皺襞は未発達で, 杯細胞の粘液放出像が多数観察される. 腸腺にパネート細胞は存在しないが, 2種類の基底顆粒細胞はしばしば観察され, 特に直腸部において多数認められる. 吸収上皮細胞の構造は他の哺乳類とほとんど同じでまた腸管各部の上皮細胞の構造にも変化は認められない. これら吸収上皮細胞間には, しばしば明調のリンパ球が散在し, 固有層には暗調の顆粒をもった特微的な細胞がリンパ球や形質細胞に混在して認められた。

Tlae existence and the distribution of the Nymph vessels in the t?amstertestis were studied morphologically in detail. By the perfusion metlaod for fixation, theNymph vessels were observed in the interstitial tissue just adjacent to the seminiferotustubules with tire light and electron microscope.The penetrating of the Nymph vessels through the albuginea testis was confirmed andas a result of tracing these Nymph xessels, the coarse net works of the Nymph capillarieswere reconstructed and figured. The lymphatic net works were recognized to anastomoseeach other and their branches were situated just close to the seminiferous tubules and tlaeinterstitial cells. In the electronmicroscopic observation, these Nymph capillaries sltowedthe closed s)stem and so their free endings were not opened.The tissue spaces had no direct communication to the Nymph capillaries but they weresuggested to form the sinusoidal pathways of the same protein-rich liquid as that in theNymph vessels, and the important role of the interstitial tissue spaces as the passages orextracellular liquid were discussed.

The intercellular junction was observed in urodeal and Phallic epithelial cells of the guinea fowl, Numida meleagris, by the ultra-thin section and the freeze-fracture methods to clarify the pathway of a lymph-like fluid produced by capillaries. Only desmosomes were found between cells of the stratified squamous epithelium covering the tips of paired lateral phallic bodies. The proximal portion of the lateral phallic body and the urodeum were lined with stratified and pseudostratified columnar epithelia containing numerous mucin-secreting cells. The columnar epithelial cells were linked with junctional complexes and cytoplasmic interdigitations. Half-desmosomes connected cells of the epithelial basal stratum with the basement membrane. The zonula occludens was well developed among mucin-secreting cells, but underdeveloped among columnar epithelial cells. When these junctions were examined in freeze-fracture replicas, the zonula occludens of the mucin-secreting cell exhibited a very distinct network of branching and joining strands. This type of tight junctions appeared to serve as a barrier to prevent lymph from diffusing by the intercellular route. On the other hand, the underdeveloped zonula occludens of the columnar epithelial cell was of incomplete reticular pattern in membrane fusion. It was suggested that the lymph produced by blood and lymph capillaries might be able to pass through the epithelium to play a part in dilution of the ejaculated semen.

In order to clarify the normal involutionary changes in the reproductive organs and adrenals which occur as a results of hypophysectomy, a histological study on these organs of hypophysectomized female mice was performed. Twenty immature and 28 mature mice of the bc strain were subjected hypophysectomy and autopsied at various periods ranging from 1 to 150 days after hypophysectomy. the operation the immature mice were 28 to 30 days of age, and the mature ones 2 months of age. autopsy, the organs to be studied were all dissected from the surrounding fatty connective tissue, weighed and prepared for histological studies. The fixatives and staining methods employed were the same as those described in our previous reports, except for some cases in which the organs were fixed in chilled 80% alcohol and stained for alkaline monoglycerophosphatase by Gomori's technic.Following hypophysectomy there was a fall in boby weight. The reproductive organs and adrenal glands regressed in weight and underwent a pronounced atrophy. The changes in organ weights are summarized in tables 1 and 2.Ovaries: A very rapid regression in size of ovaries took place. Thus there has been a loss of some 50% in weight on the 10th day after hypophysectomy. The first structures to show significant changes after hypophysectomy were large and medium sized follicles. Signs of atresia began to be seen as early as 24 hours, showing clumping of chromatin and achromatolysis of the granulosa cells. Later the thecal cells underwent atrophy, the ovum degenerated and on the 5th day no large follicles remained. Small follicles showed a gradual decrease in number and very few were seen on the 25th day, the ovary becoming to be filled with stromal cells. However, growth of the primordial follicles did not cease. They might develop to the beginning stage of antrum formation, because in the granulosa cells of the small follicles, although not numerous, mitosis were often seen. In the ovaries of prepuberally operated mice, pituitary defficiency manifestations were also evident. Since abvanced stages of follicular maturation did not occur in any case. The most interesting fact about alkaline phosphatase which has emerged from this study is that all follicles of varying size develop large quantities of the enzyme in the granulosa layer which is normally almost devoid of activity.Ovarian stroma: The ovarian stroma of the operated mice was composed of a highly cellular tissue with densely staining nuclei. The nuclei underwent a retrogressive process designated as “wheel cell formation”.Corpora lutea: When corpora lutea were present, a process of degeneration began within 5 days and ended by the 20th day after the operation. Corpora lutea of pregnancy in the mice operated at midpregnancy, however, looked quite normal at the end of gestation.Uterus and Vagina: After the operation the uterus atrophied to a small and compact structure, very similar to that found in the spayed animals. The vaginal epithelium underwent a pronounced atrophy and the epithelium consisted of two layers of cells only.Adrenal gland: The adrenal glands underwent cortical atrophy in a marked degree and their individual cells decreased in size. The histological changes produced by hypophysectomy in the adrenal glands were almost the same as those described in our previous papers, but were somewhat prominent in females. It is of considerable interest that after operation alkaline phophatase developed in the adrenal medullary cells, which is normally devoid of activity in them.

THE seminal vesicles and prostates of rats are highly sensitive to androgen. In the hypophysectomized animal the recovery and growth of the regressing organs can be easily obtained by the administration of minute doses of androgen. The maintenance (Cutuly et al., 1938) or reinitiation (Nelson, 1940) of spermatogenesis and the scrotal growth, however, were not accomplished, unless animals were treated with much larger amounts of androgen. In the study of the course of sexual maturation some paradoxical facts came to attract our attention. In our colony of rats, the significant growth of the accessory sexual organs (seminal vesicles and prostates) was never observed until about 60 days of age, while spermiogenesis, descent of testis and epididymal growth began to take place almost simultaneously at the 30–40th day of age (Suzuki, 1950a,b, 1951, 1952a,b, 1954a,b.). Why do the proper accessories fail to start their significant growth at this earlier stage of the maturation process, though these organs

著者らはさきに('61)鶏精巣の間質内に精子が存在することを報告した.その後の研究によれば,その出現は鶏の系統と関係があるらしく考えられた.今回はその点を確かめるため,独立した15系統(3品種),184羽の材料について検査して,次のような結果をえた.1. 間質内に精子を認めうる場合には,多くは単独でなく,数個ないし十数個の集団をなして存在する(+)が,尾部の構造を確認できるものは少数であつた.連続切片で精査しても,単独精子のみの場合もあつた(±).2. 単独,集団いずれの場合も,多くは同一の切片中数ヵ所以上で認めることができた.3. +,±を合せれば,15系統中4系統で認められ,品種的には殆んどが白色レグホーン(W.L.)で,ニューハンプシャー(N.H.)で1例が認められたにすぎない.4. 出現例数は,+はW.L.で6例(3系統),N.H．で1例の計7例,±はW.L. 1系統で4例がみられた.出現率:+は3.80%,±は2.17%,両者を合せると5.98%であつたが,系統別にみると,+はE種鶏場B,C系でそれぞれ19.05,4.76%を示し,1種鶏場A系では14.29%,T牧場では6.66%であり,±は19,05%(E-B系)であつた.E種鶏場B系では+,±を合せると38.09%の高率を示した.5. 日令的には,+,±いずれも殆んどが7カ月令にみられ,1力年令で2例,2～3年令鶏では皆無であつた.2～3年令鶏は少数であるから,出現と日令の関係は確言はできない.6. 本現象と品種間には特殊な関係はないように考えられる.7. 本現象の最も多くみられたE種鶏場の系統の授精率は80%以上であつた.従つて授精率を極端に低下させるものではないであろう.その他の生理的意義も不明である.8. 間質内精子の成因について,2～3の可能性が考えられたが,やはり疑問は残された.

ニホンザルの頭胴長・体重の成長曲線と共に精巣・精巣上体・精嚢・前立腺の重量および組織像について, 年齢による変化と季節的変化とを調べた. 精巣および副生殖腺の重量は, 精子形成開始期である4歳前後から著明な増加を始め, 10歳頃まで継続した. 成熟個体では, 精巣上体を除く各器官の重量が繁殖期の間で有意の差を示した. 組織学的には精細管径, 精細管断面に於ける pachytene spermatocyte の数と出現頻度, spermatid および精子の出現頻度, 精巣上体管 (体部) の管径・上皮厚・管内の精子包含率, 精嚢・前立腺 (前葉) の上皮厚などいずれも, 精子形成開始期前後から著しく増加あるいは増大しはじめ, その後10歳頃まで継続した. 精巣管内に最初に精子が観察されたのは3歳または4歳の繁殖期であった. 精嚢・精巣上体および前立腺の上皮細胞の原形質は, 繁殖期においては内腔に向かって高く伸長し, 活発な分泌活動を示す一方, 非繁殖期は細胞の高さを減ずるなど分泌活動の低下がうかがわれた.

ホロホロチョウにおける排泄腔旁脈管体の微細構造とリンパの生産機構を明らかにする目的で, アルコール割断法による走査電顕観察および凍結割断法お上び過酸化酵素 (HRP) 注入法による超薄切片の透過電顕観察を行った。雄ホロホロチョウの脈管体は被膜, 小柱, 被膜下周縁リンパ洞, リンパ洞および毛細血管索より構成されていた。毛細血管索の組織間隙には小動脈, 小静脈, 膠原線維, 線維芽細胞, 神経線維および神経終末が観察された。毛細血管の内皮細胞には飲み込み陥凹および小胞, 分泌陥凹および小胞, 辺縁空胞およびゆるい細胞間連結装置が見られ, さらに, これらの構造には多量のHRP穎粒が認められた。これらのことから, 毛細血管の内皮細胞は小動脈および小静脈の内皮細胞に比べ物質の輸送能力が発達していると推定された。

韓国在来鶏の雄14羽と雌42羽を計測し, 既報のインドネシア, フィリピンおよびマレーシア在来鶏の計測値と, 多変量解析法および単変量解析法によって比較検討した. その結果, 以下の形態学的特性が明らかにされた. (1)雄の韓国在来鶏はインドネシア在来鶏およびフィリピンとマレーシアの闘鶏型在来鶏とともに最大型群を形成する. (2)この最大型群のなかで, 雄の韓国在来鶏の形はインドネシア在来鶏およびマレーシアの闘鶏型在来鶏に似ているが, フィリピンの闘鶏型在来鶏とは非常に異なっている. (3)雌の韓国在来鶏は計測した雌在来鶏群のなかで最も大きく, さらにフィリピンとマレーシアの非闘鶏型の雄よりも大きい. (4)韓国在来鶏では雌雄間の大きさの差は著しいが, 形の差は大きくない. 本研究では8計測部位が主成分分析に用いられ, そのうち翼長と長骨長が鶏体の大きさと形の識別に, 最も適していることが明らかにされた.

The primary formation of germinal centers was induced in the chick spleen by intravenous injection of sheep red blood cells (SRBC) at 21 days of age. In the spleen, SRBC were trapped in the ellipsoids soon after injection. The number of cells of periellipsoidal lymphoid tissues (PELT) was gradually depleted. Large pyroninophilic cells appeared in the periphery of periarterial lymphatic sheaths (PALS) 4 hrs after injection. Then they increased in number and migrated centralward in the PALS. On the 4th day they were accumulated in the vicinity of the central arteries to make nodular structures. Morphologically mature germinal centers encapsulated by connective tissue were formed for the first time on the 6th day after injection. They were most numerous on the 8th day and then decreased gradually. It was presumed that the primary germinal centers in the chick spleen might have been formed by the cells of the PELT which were originally derived from the bursa of Fabricius. The process of proliferation of germinal centers in the secondary immune response was discussed.

The gastric mucosa of herbivorous field voles was examined with the naked eyes, a light microscope, and a scanning and a transmission electron microscope. Its morphological characteristics were compared with those of omnivorous golden hamsters. The stomach of the hamster consists of two parts, forestomach and glandular stomach, whereas that of the field vole is composed of three parts, esophageal sac, fundic stomach and pyloric stomach. The fundic stomach has a number of gastric glands which open by oval pits on the mucosal smooth surface. The esophageal sac mucosa and the pyloric stomach mucosa are connected with each other on the side of the lesser curvature, both the mucosal membranes being lined with stratified squamous epithelia. The mucosal surface of the esophageal sac has numerous complicated folds, whereas that of the pyloric stomach has a succession of regularly and compactly arranged protrusions. A fimbria, specific to the field vole, is observed between the esophageal sac and the fundic stomach, making a definite distinction of these two parts. The fimbria appears to strengthen the function of the esophageal sac as a fermental vat. The pyloric gland region is separated from the fundic stomach by the pyloric stomach and is located at the short part just before the duodenum. The functional roles of the pyloric stomach and the pyloric gland segment are not clear.

In the preventriculus of the domestic goose, there are the V. proventricularis dextra and V. proventriculolienalis, both of which are absent in the duck. The former is not so developed that the venous blood from the right dorsal part of the proventriculus is drained caudally by the well-developed Anastomosis cum v. proventriculari sinistra and empties into the Pars transversa of the R. sinister v. portae via the V. proventricularis sinistra. Although it is difficult to estimate the accurate distribution of venous blood of the avian proventriculus, more than half of the blood from the proventriculus of the goose is collected into the precava after passing through the V. proventricularis cranialis due to the prescnce of the poorly formed V. proventricularis dextra. In the wall of the proventriculus of the goose there is a rather dense venous network formed by anastomoses of V. proventricularis cranialis, V. proventricularis dextra, V. proventricularis sinistra and V. gastroproventricularis which empties into the V. gastrica sinistra. The systemic circulation is connected more closely with the portal circulation by this network in the goose than in duck and chicken. There are no differences between the arterial and venous supplies in the ventriculus (muscular stomach) of the goose. Arterial branches perforate the tissues of this organ in the marginal area and the intermuscular groove like venous tributaries. The proventricularis sinistra, V. gastrica intermuscularis, V. gastrica ventralis and V. gastrica sinistra empty independently into the left hepatic lobe in the goose. Since all of them have the same function in the hepatic portal system, it is proposed to use the V. portae hepatis sinistra as the general term for the four veins.

The collective volume of Leydig cells in prenatally pinealectomized newborn rats declined as sharply as in intact newborn rats. Also, the collective volume in pups born in the dark declined in a fashion similar to that in pups born in the light. The results indicate that neither the pineal gland nor the light is responsible for the neonatal shrinkage of Leydig cells.

Development of the vomeronasal organ in the golden hamster was chronologically examined by light and electron microscopy. This organ was embryologically derived from the olfactory placode and appeared as a tubular structure of the neuroepithelium on the medial wall of the nasal pit on either side at 11 days of gestation. At 12 days of gestation, this organ was completely separated from the nasal cavity and encircled by the immature vomeronasal cartilage. At 13 days of gestation, within the organ, the respiratory epithelium became easily distinguishable from the sensory epithelium. At 14 days of gestation the venous sinus and Jacobson's glands appeared, and this organ was equipped with all the histological components until birth. This organ began to communicate with the nasal cavity at 2 days after birth. The sensoly epithelium of this organ consisted of undifferentiated cells in the early fetal life. These stem cells were gradually differentiated into sensory and supporting cells. These cells were rather slowly maturated in their fine structure. For example, only some sensory cells became first provided with microvilli on their free surface at 8 days after birth. Even at 10 days after birth, some sensory cells were still devoid of microvilli and undifferentiated cells were sometimes observed in the sensory epithelium as well. Therefore, the olfactory function in the early postnatal life seems to be solely ascribed to the olfactory epithelium under these morphodifferentiation though the vomeronasal organ might be related with some kind of olfaction after this period.

An electron microscope study was made to elucidate the manner in which reticular fibers form in the developing spleen of the chick embryo. On the 7th day of incubation, the splenic reticulum consisted of dendritic reticular cells without reticular fibers. From the 9th day onward, the intercellular gaps between processes of adjacent reticular cells were expanded, becoming occupied by fine flocculent materials. With the growth of the embryos, these materials were aggregated into felt-like bands, exhibiting the characteristics of mature reticular fibers. In the interstices of the reticulum, there appeared microfibrils of 8-30 nm in diameter. The reticular cells possessed numerous free ribosomes and polysomes, well-developed Golgi apparatuses, dilated rough-surfaced endoplasmic reticula, and many coated vesicles. The coated vesicles contained fine flocculent materials as presumable fiber precursors. The vesicles were enlarged as they approached the cell periphery, where they appeared to discharge their contents by reverse pinocytosis. some vesicles close to the cell membrane contained ruthenium red-positive materials which were considered to be glycosaminoglycan in nature and to compose the matrix of fibers. These materials also seemed to be secreted by reverse pinocytosis, being densely accumulated in the intercellular gaps. The differentiation of fibrous proteins into felt-like reticular fibers or striated microfibrils seems, therefore, to be intimately associated with the amount of glycosaminoglycan.

The area of the largest transverse section and the number of muscle fibres in a unit sectional area (1 mm2) were examined in 8 trunk and 12 extremity muscles of young and adult 16 light horses and 8 ponies. It was found that the area of the largest transverse section was enlarged and the number of muscle fibres in a unit area was decreased, with the advance in age. This result suggests that the development of muscle volume does not depend on the increase in the number of fibres, but depends on the hypertrophy of each muscle fibre.