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1. Six-hundred and seventy-three Wistar and W/Fu rats were treated at the age of 4 months with whole body x-ray, orally administered 3MCA or a combination of these agents. All animals were followed until death and 87 per cent were autopsied. 2. Among 303 autopsied animals there were 403 benign and malignant tumors, including 28 leukemias. 3. Differences were noted in the incidence and types of leukemia occurring in both breeds of rats. In Wistars 9 of 11 leukemias were myelogenous and 8 of these followed x-ray exposure. 4. Approximately a 10 per cent incidence of spontaneously occurring mononuclear cell leukemia was found in W/Fu rats; exposure to x-ray apparently decreased the occurrence of leukemia in these rodents. Following oral administration of 3MCA, 13 per cent of W/Fu rats developed acute mononuclear cell leukemia. 5. Results of hematologic, cytologic and histochemical studies on rat leukemia are discussed in this article, and the possible significance of the appearance and disappearance of the distinctive mononuclear cells in the peripheral blood is pointed out. 6. Pathologic findings indicate that the majority of deaths, other than those due to leukemia, were due to pulmonary infections and a great variety of tumors. In leukemic animals enlargement of the spleen was almost universally present and adenopathy, especially involving mediastinal and retroperitoneal glands, was frequently noted. Among 9 myelogenous leukemias in Wistar rats green chloromatous tissues were found in 5 animals. 7. Cytogenetic studies were carried out on direct preparations from the bone marrow in most of the leukemic rats in this series. Aneuploidy was noted in several animals and one W/Fu rat demonstrated a morphologically abnormal "marker" chromosome. In more recent studies improved technics and use of the spleen as a source of metaphase preparations have afforded better opportunities to obtain adequate chromosome preparations in leukemic rats. Further investigations are in progress and special studies are being directed to the viral and cytogenetic aspects of leukemia in the rat.

The Racial Perceptions Inventory (RPI), a 66-statement inventory measuring racial attitudes and perceptions, was designed to assess the racial climate of military posts. Responses of 1,385 soldiers at three different army posts were used in the development and validation of three reliable scales dealing with different aspects of race relations in the military: Attitudes Toward Integration (ATI), Perceptions of Racial Discrimination (PRD), and Backlash Feelings (BF).Racial perceptions tapped by the PRD and BF scales are highly associated with the race of the perceiver. Aside from race, surprisingly few other demographic variables were substantially associated with perceptions of every day military life. ATI scores showed little crossracial difference but were linked to premilitary contact with other races and career commitment to the military. Uses of the RPI in intervention planning and evaluation are suggested.

A simple capacitor transducer for measuring blood pressure in small experimental animals has been constructed. A hypodermic needle closed at its collar end by a brass diaphragm was used as the cell of the transducer. A thin plastic sheet was used as the dielectric, inserted between the diaphragm and a slightly convex brass rod serving as the other plate of the capacitor. The whole assembly constitutes a capacitor whose capacity varies inversely with the pressure as the space between the two plates changes. The transducer can be coupled directly to a conventional R. F. generator, preamplifier, and pen-writing oscillograph assembly. Results show that this simple transducer is very rugged and has a high degree of zero stability. Its sensitivity is very great, accompanied by a very small resolution time. Its accuracy is well demonstrated by the detailed recordings of the central pulse contour in normal and hydralazine-treated rats.

This paper describes a programmable high voltage power supply. It is capable of delivering triggered currents of up to 100 ma at 400 volts. The compelling reason for its design and construction was in order to reduce inherent functional complexity built into some existing commercial systems. This was accomplished by redesignings the power supply, trigger controls and metering components. Control of the lamp current was effected by changing the screen grid voltage, thereby leaving the control grid to be used exclusively for switching. This resulted in a calculated rise time of less than five micro-seconds. The device herein described was used as a direct replacement in the Techtron A.A. Spectrophotometer. When used at switching times of more than 400/sec it supplied accurate phase control with minimum background noise. The following four figures describe the apparatus in detail.

It is often useful to maintain an analogue output of a signal which has excessive noise. At near D.C. frequencies, this is seldom possible. However, when the noise can be identified, two ways of correcting this situation are immediately available. The first is to eliminate the interference at the source and the second is to supply appropriate offset to this interference. In the case of high-level energy sources, it is virtually impossible to eliminate their interference and it becomes necessary to fabricate electrical offsets to do this. This procedure is well-established in electronics and is used extensively in operational amplifiers.

1. Adequate chromosome preparations were obtained in 70 per cent of normal rat peripheral blood cell cultures. However, cultures of peripheral blood cells from leukemic rats were almost universally unsuccessful. 2. In x-ray- and 3MCA-induced leukemias direct bone marrow preparations provided adequate metaphases in eight of 12 cases. Failures were attributed in four cases to scanty material obtained from fibrotic marrows. 3. No consistent chromosome abnormalities, such as those reported in human myelogenous leukemia, were found in these leukemic rats. However, the series of cases is small, and species differences and other factors may have influenced the results of these studies.

Observations on growth and other characteristics of subcutaneously transplanted chloroleukemia in non-inbred rats have been described in this report. This chloroleukemia cytologically is an acute or subacute, not chronic, myelogenous leukemia. Because of serious immunologic differences, the experimental usefulness of subtransferred chloroleukemia is greatly limited. However, myelogenous leukemia in the rat, induced by chemical agents or ionizing radiation, may offer a valuable approach to the study of leukemogenic mechanisms.

A simple method for transplantation of autologous bone and marrow to the rat kidney is described and the usefulness of this preparation for research on bone and marrow growth is pointed out. While an induction mechanism cannot be conclusively ruled out by these studies, the histologic evidence strongly supports the concept that growth of implanted bone and marrow is due to survival of small islands of active bone and marrow cells and from these foci, repopulation takes place.

Ten groups, five to ten animals per group were used in demonstrating that progesterone plus cortisol acetate can induce implantation and maintain embryonic growth in hamsters subjected to ovariectomy and adrenalectomy on Day 1 or on Day 4 of pregnancy. Fetal weights on Day 14 were, however, significantly lower than in sham-operated control animals, although they were not different from those in animals only ovariectomized and given progesterone. It is concluded, therefore, that it is unnecessary to invoke secretion of estrogen either from the ovaries or from the adrenals for induction of implantation in hamsters.

An analytical system capable of recording continuously and practically instantaneously changes in sulfur dioxide concentration in air has been developed. The method requires a relatively small volume of gas sample for analysis. Contaminated air reacts with acidified hydrogen peroxide solution in a counter-current absorber to form sulfuric acid. The impedance of the effluent bears an inverse relationship to the amount of sulfur dioxide being absorbed ranging from 0-500 ppm. Changes in impedance are detected by two parallel electrodes when the predetermined, high frequency voltage across them is disturbed. The applicability of this technique for other gases and studies is discussed.

The structures previously assigned to two constituents of Diospyros hebecarpa A. Cunn. are confirmed by the synthesis of 5-hydroxy-7-methyl-l,4-naphthoquinone and its conversion to 1,4-diketo-5-hydroxy-7-methyl-1,2,3,4-tetrahydronaphthalene. By an independent route 5-methoxy-7-methyl-l,4-naphthoquinone has also been prepared, and has been converted to 1,4,5-trimethoxy-7-methylnaphthalene.

The reaction of dimethylamine with 5-methoxy-1,4-naphthoquinone gives approximately equal amounts of the two possible substitution products and with 6-methyl-1,4-naphthoquinone followed by acid hydrolysis 2-hydroxy-6-methyl-l,4-naphtho-quinone is the principal product. Similar treatment of 5-methyl-1,4-naphthoquinone gives mostly 3-hydroxy-5-methyl-l,4-naphtlioquinone. The isomer, 2-hydroxy-5- methyl-1,4-naphthoquinone, has been prepared by another method. The product of Thiele-Winter addition of acetic anhydride to juglone is shown to be a mixture of the two possible isomers, but authentic 1,3,4,5-tetra-acetoxynaphthalene has been prepared from 3,5-dihydroxy-1,4-naphthoquinone. The reaction of acetic anhydride with plumbagin gives three compounds, the composition of the mixture depending on the time of contact. Juglone and plumbagin have been selectively brominated in the 6-position and certain other halogen derivatives of these quinones have been prepared. The preparation of 3-chloro-5-hydroxy-2-methyl-1,4-naphthoquinone provides a new route by which droserone may be obtained from plumbagin.

Ether extraction of Diospyros hebecarpa A. Cunn. yields plumbagin, and two new compounds which are shown to be 5-hydroxy-7-methyl-1,4-naphthoquinone and 1,4-diketo-5-hydroxy-7-methyl-1,2,3,4-tetrahydronaphthalene. The ultraviolet absorption spectra of these and related compounds are recorded, and the synthesis of 1,4,5-tri-methoxy-7-methylnaphthalene is described.

Sixty-four men who had notably few urinary complaints progressed from bladder neck obstruction to uremia. Contrary to popular belief, they were not neglected, feeble hermits whose senses were obtunded by past excesses or senility. Physicians, their fathers, and clergy comprised one-fifth of this series. Intelligent men often accepted bladder symptoms as "normal acquisitions" of age. The diagnosis was delayed when unsuspecting physicians were misled by the deceptive rectal finding of a "small prostate." Men undergoing abdominoperineal resection are particularly prone to development of silent prostatism. Liberal use of blood urea nitrogen determinations and intravenous pyelograms are advocated in men having even slight evidence of abnormality of the bladder neck. In retrospect, cautious bladder decompression in the hospital is still advised as an initial step in management. Thirty-two men (50 per cent) remained uremic.

A threshold gas Cherenkov counter with an aperture of 26 cm and an overall length of 97 cm has been constructed. It is designed to distinguish pions from kaons and protons in the momentum range from 1.3 to 3.0 GeV/c. Its optical design allows the collection of Cherenkov light from the whole length of the counter, resulting in a detection efficiency of over 99% and a high rejection ratio for delta rays from below-threshold particles. Its short length and low pressure (< 165 psi) effectively minimize multiple scattering of the detected particles.

Modern students of tuberculosis believe that tuberculous infection usually comes in childhood and that it may develop then, or be quiescent, or be cured. If quiescent, it may show renewed activity at later periods of life. Baldwin1 says:Childhood is the time of infection, youth the time of superinfection, and that from extension of the primary disease.McCleave2 says:It is now generally conceded that infection with the tubercle bacillus is, in the majority of cases, an incident of early life, and that, regardless of the time of development of clinical symptoms, tuberculosis is, in its origin at least, essentially a disease of childhood.Francine3 says:This infection during childhood does not, as a rule, develop into pulmonary tuberculosis at that time, but lies dormant in the lymphatic system, or is latent until adult life, when it breaks forth or manifests itself in pulmonary localization. It is

Three instances of ileal replacement of the ureter, involving both right and left sides, male and female, child and adult, are reviewed. The actual and theoretical pitfalls are reviewed and their avoidance is discussed.

Common gastrointestinal complications preceding or following renal homografts, with particular emphasis on gastrointestinal hemorrhage, hepatitis, and pancreatitis.