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麻布獣医科大学家畜解剖学教室,相模原市229反芻類においては,腹腔臓器に対する横隔膜の付着様式は,反芻に大きな意味を持つものと思われる.本研究においては,牛胎仔および新生仔を用い,とくに胃に対する付着様式をホルマリン固定した材料および胸腔•腹腔ならびに消化管への合成樹脂注入鋳型標本を観察することによって調べた.横隔膜と食道および胃との接着部では,食道尾側端および噴門部の表面には主として右脚から筋線維が分布していた.胃に対する主な付着は左脚からの筋線維によるものであった.胃に対する横隔膜の付着領域は,前方よりみて逆V型を示す.この逆V型を形成する左右両板のうち右板は,右脚からの筋線維とともに噴門付近を被い,背方に向かって第1胃前房背側面から第1胃背嚢右側背縁に至っていた.この逆V型の左板は第2胃背面より後方に向かい,第1胃背嚢左側背縁および脾臓に至っていた.両板の背後側端における連結部は,胎仔においては非常に薄く,新生仔に至って厚く,広く,強靱となった.これらの両板の間および橋状の連結部の下には,疎性の結合組織を伴なった漿膜に被われた盲管状の空隙があり,それによってその下に位置するいわゆるNICKEL et al.のいうSchleudermagenは常に横隔膜への付着から遊離していた.以上の観察結果は反芻機構の考究に一つの参考所見として役立つであろう.

Forty-nine adult male mice were starved for 1 to 7 days. All animals except 5 for control were divided into 7 groups and sacrificed group by group every day. The adrenals obtained were studied by means of histological techniques, especially of lipid and mitochondrial staining. The results and the discussion are summarized as follows.The adrenal represented significant hypertrophy in only one day's starvation and was extremely hypertrophied by the 3rd day followed by a decrease in size close to that of the control by the 5th day. No significant difference in weight of the adrenal was obtained between the 5th and the 7th day. Lipids diminished greatly in the inner cortex of the gland 2nd day. Mitochondria hypertrophied on the 2nd day and showed a decrease in size and number on the 3rd day. There were two types in the cytological changes from the 3rd day on. In one type little lipid and few mitochondria accumulated, while in the other a large amount of lipid accumulated and mitochondria hypertrophied. Sudanophillia shown in the adrenal cortical cells had an intimate relationship with the adrenal secretory activity and mitochondria were very sensitive indicators of cellular secretory activity. From this point of view, it can be supposed that the prompt release of hormonal substance in cortical cells may have occurred by the3rd day, and that the adrenal, from the 3rd dayon, showed no function, after releasing all of thesecretory substances or storing them excessively and being unable to discharge them at all. From the 5th day on, cortical atrophies and degenerations were observed here and there in the adrenals.Figs.2-6 were stained with hematoxylin-eosin, and fig.7 with Mallory-azan. Figs.8-10 show lipids in the adrenal cortex and figs.11-13 mitochondrial distribution in the adrenal cortex.Fig.2 Adrenal cortex of a control mouse.Fig.3 Adrenal cortex of a mouse starved for 3 days. Note the remarkable increase in width of the cortex.Fig.4 Adrenal cortex of a mouse starved for 7 days. Note the remarkable decrease in width of the cortex and striking atrophy of the cells, compared with those in fig.3.Fig.5 Adrenal cortex of a mouse starved for 5 days. The cortical degeneration is present.Fig.6 A portion of the cortical degeneration which occurred in the adrenal of a mouse starved for 5 days, shown under high magnification.Fig.7 A portion of the innermost part of the adrenal cortex of a mouse starved for 5 days. The special zone is present between the innermost zona fasciculata and the medulla.Fig.8 Adrenal cortex of a control mouse.Fig.9 Adrenal cortex of a mouse starved for 3 days. Note the extreme decrease in the content of lipid in the inner cortex.Fig.10 Adrenal cortex of a mouse starved for 7 days. Note the extreme accumulation of lipid. This animal died before sacrificed.Fig.11 Mitochondrial distribution in a control mouse.Fig.12 Mitochondrial distribution in a mouse starved for 3 days. Mitochondria in the inner cortex decreased in size and number.Fig.13 Mitochondrial distribution in a mouse starved for 7 days. Note the extreme accumulation of mitochondria particularly in the inner cortex.

The gonads of 9 male and 9 female fetuses of the cattle were used in this study. The fetuses are 5.7 to 45.0 cm in "crown-rump length" in males and 16.3 to 38.0 con in females. The gonads were fixed in 10% formalin and ZENKER-formol. Routine alcohol dehydration and paraffin embedding were practiced. Sections were cut at 7μ. stained with hematoxylin-eosin or HEIDENHAIN's iron alum hematoxylin, and after MASSON's trichrome method, VAN GIESON'S method and BIELSCHOWSK Y-MARESCH reticulm method. The following observations were made.Testis: There is a cuboidal layer of germ epithelium in the testis of a 5.7-cm-long fetus It becomes flattened gradually with ages. With the vascularization in the tunica albuginea, there is a remarkable increase of connective tissue fibers in the vascularized areas. The seminiferous tubules are distinctly limited by a membrana propria, exterior to which is a thin layer of small connective tissue cells forming a capsular investment. The tubules consist of two kinds of cells, i. e., indifferent cells and germ cells. The former is numerous and the latter a few. Both cells in the tubules have a tendency to increase in number, the numerical ratio between them being scarcely altered in all testes used. Interstitial cells are found sparsely at first and then form cluster-like masses with gradual vascularization.Ovary: In 16.3-cm-to 18.5-cm-long fetuses, the sex cords having a broad hand-like appearancee contain many small indlfferent cells and a few germ cells. Primary follicles increase gradually in the inner part of the cortex. In the bodies of 25-cm-and 27-cm-long fetuses, the sex cords manifested a degenerated appearance. Meanwhile, in a fetus grown 30.0-cm-long, the remarkable change is noticed with the increase in replenished sex cords. Therefore, it is presumed that the sex cords have newly been formed descending from the germ layer, or reconstructed from the parenchymal tissues in these growing stages. No interstitial cells have been found in any ovaries used.The origin of the interstitial cells in the testisand of the medullary cords in the ovary is also. discussed briefly.

The present study was conducted to clarify the histological differentiation of the adrenal cortex of the bovine fetus and to determine the time when the sudanophilic lipid appears for the first time in the adrenal gland. Twenty bovine fetuses, from 13 to 43cm in C.R.L., collected at a slaughter house in Osaka were used in this study. Fixed with 10% formalin, one of the adrenals of each fetus was paraffin-sectioned at 7μ in thickness and stained by several methods; the other was frozen-secti ned at 25μ and stained with Sudan IV-hematoxylin. The observations are summarized as follows. At the stage of a 13-cm C. R. L., the cortical parenchyma was composed of irregular cell cords alone. At that of a 16-cm C.R.L., beneath the capsule were revealed rather slightly smalloepitheloid cells grouped in spherical clusters. A layer of these clusters of cells is to be termed zona glom-erulosa. By the stage of a 24-cm C. R. L., the spherical clusters beneath the capsule developed further and expanded horizontally along the capsule with widening connective tissue spaces among them. The cells of z. glomerulosa were smaller and stained darker than those of z. fasciculata. Histolo-gical differentiation of the adrenal cortex of the bovine fetus seemed to be almost completed essen-tially by the stage of a 30-cm C. R. L., because little changes were found in the gland after this stage. Few sudanophilic lipid droplets were found in the parenchyma of the adrenal cortex of a 19-cm-long fetus. In a 24-cm-long fetus, however, sudanophilic droplets were contained in some cortical rPlls, especially in the glomerular and the inner fasciculate cells in considerable abundance. From the stageof a 27-cm C. R. L., on all adrenals contained lipid droplets in the cortex with no exception. From the stage of a 27-cm C.R.L. on, lipid droplets gradually increased their size and number in the glomerular cells. As the lipid contained in the adrenocortical cellsis said to have an intimate relatiorship with hormone production, it may be concluded presumably from the above observations that the adrenal of the bovine fetus may shows in some manner the hormone-formation or the secretory activity, at least after the growth stage of a 27-cm C. R. L.

Thyroids of 26 bovine fetuses, 10.0 to 64.5 cm in crown-rump length, were histologically examined. The number, body length, and estimated age of the fetuses are shown in table 1. The glands were fixed in Zenker-formol and embedded in paraffin. Paraffin sections were stained with hematoxylin-eosin and by Masson's trichrome method, Mallory-azan method, PAS technique, and LILLIE's silver impregnation.In a 10-cm fetus, the thyroid consisted of undifferentiated epithelial cells arranged in very irregular cords. In a few of these cells, the cytoplasm contained colloid droplets, which were also seen in intercellular spaces. No follicles were present, In 12.5-and 13.2-cm fetuses, a few very young follicles with a colloid mass in the lumen were developed in the cords and spherical groups of cells, most of which were loaded with colloid droplets located in juxtanuclear portion or far from the nucleus, or polarized toward the capillary surface. From the stage of 16.3cm onwards, the whole thyroid consisted generally of follicles of widely varying size which grew progressively together with an increase in amount of colloid stored in them which stained mostly blue or occasionally yellow or red by the azan method, except the peripheral portions of the gland which presented indifferent patterns showing irregular cell masses and very young follicles.Argyrophilic granules demonstrated by LILLIE's silver impregnation appeared in fetuses 16.5cm in body length and older, first in cells of small follicles and then in these of medium-sized follicles and of interfollicular undifferentiated epithelial masses. Follicles were formed first in irregu'ar cell cords and, thereafter, separated by encircling of argyrophilic fibers, growing by mitotic proliferation of cells, together with their fellows developing from interfollicular undifferentiated epithelial cells.Most cells of the developing follicles contained PAS-positive, occasionally argyrophilic, granules in the apical portion of the cytoplasm being ready to cast them off into the lumen. With the advance of fetal age, colloid substances became to be seen frequently in the interstitial tissues in variable amount. They may be extravasations pushed out of ruptured follicles or passing through degenerating colloid cells in the follicular epithelium from the lumen.