Electrical parameters in two methods of stimulation, i. e. the rectal probe method under anesthesia and the penile method in consciousness, were examined in the Japanese monkey (Macaca fuscata) . In rectal probe method, ejaculation occurred in almost all animals by the stimulation of intermittent charges of 10-15 volts at a frequency of between 3-5 impulses per second by using a monophasic alternating current of 60 cycles. In penile method, good results were obtained by a DC, square wave stimulus applied with a frequency of 18-20 pulses per second and a duration of 20 milli-seconds per pulse. Animals required some training period for the penile method initially, but they responded well after sufficient practices. Although the semen samples obtained by the penile method showed spontaneous liquefaction partially at all times, samples by the rectal probe method frequently stayed in absolute coagulum. The fluid portion in the specimen by the penile method contained free, motile and rich spermatozoa in contrast with the rectal probe method that included little sperm in it. The details of stimulation and the observation of liquefaction are presented and discussed.

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The present study was carried out to determine if alterations in steroid producing ability of ovary could account for the abnormal embryonic developement which follows delayed ovulation. The rats treated for 1 or 2 days with Nembutal were used as the animal model with delay of ovulation. In normal rats before the ovulation, the ovaries secreted predominantly estradiol-17β (E₂) and later, after the ovulation, produced mainly progesterone (P) and 5α-dihydroprogesterone (5α-DHP) . In rats that failed to ovulate, the levels of E₂remained high on the first day of blockade and decreased to very low levels on the second day of blockade, while P and 5α-DHP remained at low levels during this period. After the ovulation which follows delayed ovulation, there was still a shift in the steroid secretory patterns, which was similar to that observed in the normal ovaries. However, the concentration of 5α-DHP was significantly lower than that after normal ovulation. The injection of LH greatly increased the secretion of 5α-DHP within 30 min in both the normal and the blocked ovaries, but the steroid-producing ability of ovaries which follows delayed ovulation was low, suggesting low 5α-reductase in the ovary with delayed ovulation. It is said that physiologic effect of 5α-DHP is concerned in life of blastocysts. These results suggest that the abnormal embryonic development which follows delayed ovulation may be causally related to the low 5α-reductase activity in the blocked ovaries.

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The low plasma alkaline phosphatase (ALP) activity of the IS strain of rats was genetically analized by using the cross matings with the BN strain. In the F₁hybrids, the ALP activities were intermediate but largely biased to the low activity. In the (F₁×BN) back-cross progeny, the distributions of plasma ALP activities were apparently bimodal in both sexes.Al p-2locus with two alleles ofAlp-2^handAlp-2^lis tentatively proposed.Alp-2locus did not link to the rat linkage group (LG) I, II, IV, V, and LGs containingAmy-1and Cs-1. In the (F₁×IS) back-cross progeny, the plasma ALP activities were not different from that of the F₁hybrids and the distribution was not bimodal.Alp-2^lmay be dominant overAlp-2^h. One third of the back-cross progeny showed vertebral anomalies and the difference of plasma ALP activities was not detected between the rats with and whithout vertebral anomalies.

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C6 deficient rabbits were found in a breed of Angora rabbits reared in Japan. The genetic studies confirmed that this complement deficiency was transmitted as an autosomal recessive trait. Alloimmunization of the deficient rabbits with normal rabbit serum produced a specific antibody to C6 component. This antiserum cross-reacted against human, cattle, sheep, goat, pig, dog, guinea pig and mouse serum, but not to horse, hamster and chicken serum. The C6 levels in the sera of Angora rabbits, measured by the single radial immunodiffusion method using the alloantiserum, were distributed in three distinct group; normal, about half of normal and null level. The C6 level in the sera of Fl rabbits (C6⁺/^-), crosses between C6 deficient Angora rabbit (C6^-/^-) and New Zealand White rabbit (C6⁺/⁺) was about half of normal level. These results suggested that the level of C6 in the sera was under the dosage effect of C6 deficient gene.

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In the laboratory cat colony consisted of 14 Korats and 8 Japanese native cats, the disease characterized by upper respiratory signs occurred. Seven cytopathogenic agents were isolated from the oropharyngeal swabs and necropsy materials of affected cats by means of inoculation to primary feline kidney cell cultures. One of the isolates (KS-1 strain) was identical with feline herpesvirus (FHV), and was appeared to be a causal agent of the trouble. Properties of the KS-1 strain were in general agreement with the known strains of FHV. Serologic examination and clinical analysis suggested that Japanese native cats became carriers, reexcreted the virus and spread it to susceptible cats. Virucidal activities of several disinfectants against FHV, comparing with a feline calicivirus (FCV), were studied and the following conclusions reached: 1) Sodium hypochlorite, iodine complex, benzethonium chloride and chlorhexidine were effective against FHV at commonly used concentrations. 2) Among chemicals tested sodium hypochlorite was most effective against FCV and followed by iodine complex. 3) Benzethonium chloride and chlorhexidine had little efficacy against FCV at commonly used doses.

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An improved mouse metabolism cage, remodeled after the conventional makeshift type to permit accurate measurement of urine volume, avoiding or minimizing fecal contamination of urinary constituents and undue stress on the animal under test, is described. The structure of the cage is illustrated in detail in Figures 1 and 2. The principal points of modification include: 1) a semi-level top surface of the glass globe separator to accommodate the mouse in a less stressful posture of reduced instability; 2) a steeper gradient of the lateral spherical surface of the glass globe separator avoid contamination of urine by feces, drinking water leaks and debris of diet, along with a shortened urine collecting tail (27mm) and a receptacle for watar leaks; and 3) an insulator installed at the bottom to prevent escape of the animal. Performance tests of the cage demonstrated accurate measurements of urine output and water intake and assays of urinary constituents, with complete prevention against escape of mice.

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Several parameters on pregnancy and parturition of primiparous Sprague-Dawley rats were examined. Interval between placing with males and pregnancy averaged 7.4±1.1 days and 75% of rats became pregnant within 10 days after mating (Fig. 1) . Presence of sperms in the smears showed much higher pregnancy ratio than the other two indices, vaginal plug and the last estrus (Table 1) . Pregnancy period was mostly 23 days when the day of appearance of each copulaiton sign was designated as 1 day of pregnancy (Table 2) and all rats started parturition during light time of animal room (7 : 00 AM 9 : 00 PM) on both 22 and 23 days of pregnancy (Fig. 2) . Average time required for parturition was 105±10 minutes and mostly less than 2 hours (Fig. 3) . There was no correlation between litter size (12.6±0.5 : Fig. 4) and the time required for parturition. The ratio of still-born pups was 1%.

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Mouse hepatitis virus (MHV) infection occurred in athymic (nude) mice transplanted with human malignant tumors and 28 out of 38 tumor lines were contaminated with MHV. These 28 tumor lines were passaged in pathogen-free nude mice and 15 of these tumor lines (53.6%) became MHV-free. The MHV infection was eliminated in more than half of the tumor lines by passaging.

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