The effects of removal of the olfactory bulbs on the estrous cycle and the weight of reproductive organs were examined in mice of the IVCS, ICR and C57BL/6 strains. Sham-operated and intact mice served as controls. Virgin female mice were surgically deprived of the olfactory bulbs at 8 weeks of age and caged individually in air-conditioned rooms with controlled lighting (14 hours of light, from 5 a. m. to 7 p. m., each day) . Vaginal smears were observed daily. The animals were killed and their principal organs weighed at 6 weeks after the operation. The results obtained were as follows ; 1) The olfactory bulb ablation prolonged the length of estrous cycle of mice of the ICR (6.0 days) and C57BL/6 (5.0 days) strains, but did not modify the cycle in those of the IVCS strain (4.0 days) . 2) A decrease of ovarian weights by this operation was observed in the mice of the IVCS and ICR strains, but not C57BL/6 strain.

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The mandibular glands of the Chinese hamster were examined by light and electron microscopy. The mandibular acinar cells were noted to be categorized in a seromucous type, because the acinar cells stained slightly basophile and moderately positive for periodic acid-Schiff (PAS) and alcian blue (AB) reactions and the intercellular canaliculi were detected in the cells. The acini were composed exclusively of light cells containing various secretory granules. The acinar cells exhibited a sexual dimorphism ; in the female AB staining was more intense, and also the granules having the matrix of a fine hair-like material were more numerous than in the male. Intercalated duct cells were composed exclusively of light cells and contained round and polygonal granules. The striated ducts consisted of two distinct portions, the secretory and typical striated portions without secretory granules. The epithelial cells of secretory portion were columnar in shape and contained acidophile granules which gave a strongly positive PAS reaction, and comprised light and dark cells containing secretory granules varying in size and density. The epithelium of typical striated portion was composed of both light and dark cells containing fine vacuoles and vesicles, but no secretory granules. No sexual dimorphism was detected in the striated duct.

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The expression of mammary tumor virus (MTV) antigen in the milk and various organs of three non-inbred dd mouse stocks (ddO, ddN and ddY) was examined by the immunodiffusion (ID) and micro-immunodiffusion (micro-ID) tests. The rate of MTV antigen expression in the milk was 100% at the first lactation in dd0 (6/6) and ddN mice (10/10), and 23% in ddY mice (3/13) . Mammary tumor incidence was 13% (mean tumor age : 12.0 months), 32% (9.6 months) and 10% (11.5 months) in ddO, ddN and ddY mice, respectively. In F₁hybrids between MTV-free BALB/c females and dd males, a high level of MTV antigen was detected by the ID test in the milk of (BALB/c×ddO) F₁, however, the levels in (BALB/c×ddN) F₁and (BALB/c×ddY) F₁mice were low at the first lactation and elevated with the advance of lactation number. Mammary tumor incidence had a trend to be higher and earlier in these F₁hybrids than in non-inbred dd stocks. The development of mammary tumors and detection of MTV antigen in F₁hybrids indicate the extrachromosomal transmission of MTV by male dd mice. The micro-ID test has shown that the mammaty tumors, mammary glands, male genital organs except for the testis and the salivary gland expressed MTV antigen, with a high frequency of suggesting that secondary male genital organs may play an important role in MTV infection in mice.

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Infectivity and pathogenicity ofBordetella bronchisepticato rabbits were investigated by intranasal inoculation of the organism to suckling and young animals. Results are summarized as follows. 1. By inoculation of 5×10⁴and 10⁶organisms, the infection developed in 60% and 100% of young rabbits, respectively. 2. In young rabbits, the growth of the organism was evident in the trachea within 5 days after inoculation and in the lung on the 10th day. The organism began to disappear from the lung and trachea of some animals from the 40th day after inoculation, but remained in the external nares and nasal cavity of all animals even on the 90th day. Neither clinical sign nor pneumonic lesion was observed in any stages of the infection. 3. Pneumonic lesions and serous nasal secretion were found in all suckling rabbits by inoculation of 5×10⁶organisms, but no fatal case was detected.

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Nest-building behavior in 6 female and 6 male mice of IVCS strain, 20 to 30 weeks old, was studied over a period of 24 days. Weight and style of the nest were used as measures to assess the effects of pup exposure on nest-building. Data were collected between 13: 00 and 14: 00 of each day. Female mice with pup exposure showed significant increases in the nest weight and the percentage of good-excellent nest, while males did not respond.

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Histochemical studies were performed on glycosaminoglycan (GAG) components in Wilms tumors of rats and rabbits and fetal kidneys of rats. 1. Wilms tumors. The interstitial components had an intense stainability with Alcian blue, and digestion test with hyaluronidase and chondroitinase was intensely positive. The epithelial tumor cells, showing a tubular pattern, were also stained with Alcian blue. The enzyme-digestion test was positive in the basal portion of the tumor cells, whereas it was negative in the free surface of the cells. 2. Rat kidneys. In fetal rats, the epithelial cells as well as the interstitial components were stained with Alcian blue, and the enzyme-digestion test was intensely positive. However, in adult rats, Alcian blue-stainability in the free surface of the tubular epithelium was not abolished by treatment with hyaluronidase and chondroitinase. The substance in the free surface seemed to be consisted mainly of heparan sulfate. Although the physiological significance of GAG in the cell surface cannot be deduced, it is quite conceivable that GAG, especially heparan sulfate, plays an important role in fluid absorption and transportation.

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Four groups of mice immunized with Sendai virus in different ways, namely convalescent (CT), intrapertoneally (IP) or intranasally (IN) immunized with the inactivated virus and non-immunized (NOI), were challenged and examined degree of immunity and body weight changes. Degree of immunity assessed based on the antibodies, the lung lesions and the lung viral titers was higher in order of CT, IP, IN and NOT. Body weight changes, expressed by both the decrease in mean body weights and the oorrelation corefficients between pre-and post-challenge, were less in the mice with higer immunity against Sendai virus.

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Natural transmission ofEntamoeba histolyticafrom infected mother Cynomolgus monkeys (Macaca fascicularis) to their newborn infants was investigated by the stool examination under indoor individually-caged conditions. Every infant became positive forE. histolyticabetween 5 and 10 weeks after birth. Although some infants were demonstrated to harbor the trophozoites, no overt amebic diarrhea occurred in any of the infants throughout the period of this study.

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Age-related changes in phospholipid and free cholesterol contents of hindleg muscles fromnormal and dystrophic (C57BL/6Jdy/dy) mice were investigated. Free cholesterol contents in liver, whole blood and brain of dystrophic mice at 3 weeks of age were also compared with the control. Free cholesterol content tended to increase in the liver of the dystrophic mouse. Free cholesterol content of dystrophic muscle was significantly higher than that of normal muscle at each age (2.1 to 30 weeks old), while phospholipid contents in dystrophic muscles were nearly equal to those of the normal in age from 4 to 20 weeks.

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