The effects of season on conception, sire and sex of a calf, calving number, number of calves and region of feeding in Okinawa Prefecture on gestation period of cows were analyzed in Japanese Black cattle. Data used for the analysis were records on 5, 552 calves produced by artificial insemination and registered to the Okinawa Animal Breeding Association in 1982. Means, standard deviations and 95% confident intervals of the gestation period in days were 285.2±4.6; 285.0-285.4, 286.2±4.6; 286.0-286. 3, and 285.7±4.7; 285.6-285.8, in cows delivering female and male calves and in total of them, respectively. The linear regression coefficients of the gestation period for the number of calves and calving number were -5.2 and 0.8, respectively. Gestation periods for female calves were about one day shorter than those for male calves. The gestation periods of cows on both Miyako and le islands, where animals were fed in stalls, were longer than those in Ishigaki and other small islands where feeding included grassland tethering. The gestation periods for cattle inseminated in autumn were shorter than those inseminated in spring. The gestation periods for calves born in spring and summer were shorter than for autumn and winter. Percentages of variance components for the number of calves, the breeding bull and the calving number were estimated as 59.4%, 2.7% and 1% of the total variance of the gestation period. Heritabilities with standard error estimates as calculated as those from sire to female, male and either sex of calves were 0.293±0.080, 0.255±0.077 and 0.293±0.072, respectively.

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Fundamental statistics were obtained and the normality of distribution was assessed for of corpora lutea, implantation sites, female embryos, male embryos and the total number of embryos of both sexes in 445 uteri of rats. The data for these purposes were obtained from cesarean sectioned females of SPF Wistar-Imamichi strain during June 22nd to August 20th, 1990.
Averages in a uterus were 17.64, 15.24, 7.24, 7.01 and 14.26, and standard deviations, 2.67, 2.59, 2.23, 2.43 and 2.63. The normality of distribution was based on the numbers of female emryos and those of male embryos, assuming skewness to be 0 and kurtosis, 3 and from accumulated relative frequencies on normal probability paper. The distributions of the numbers of both female and male embryos in a uterus thus appears to be essentially normal. The normality of distribution could not be determined from the sum of embryos. However, when the numbers were devided into two groups, one 9 and over and the other 8 and below, the normality of distribution was not denied nor was the litter size in a previous paper. The normality of distribution was denied on the numbers of implanta-tion sites, but a similar tendency was found on normal probability paper to the total number of embryos. However, when the numbers were devided into the same two groups as those of the total number of embryos, normal ity was denied again. Both the real numbers of copora lutea and those converted to logarithms were denied on for normality of distribution.

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Each corelation between two items was examined for the numbers of corpora lutea, implantation sites, female embryos, male embryos and the sum of embryos of both sexes in 445 uteri of rats. The data examined were the same as those in a previous paper, i. e., data obtained from cesarean sectioned females of SPF Wistar-Imamichi strain during June 22nd to August 20th, 1990.
All correlation coefficients were significant at the 1% level. A coefficient between the numbers of female embryos and male embryos was negative, whereas the others were positive. A statistically rejecting ellipse at the 1% level was drawn on a correlation diagram between the numbers of female embryos and male embryos, between the numbers of female embryos and sum of embryos and between the numbers of male embryos and sum of embryos. A “horn”, a designation by the authors, could be detected on the left lower side of each ellipse.
Wakafuji et al. reported all female rats mated with a certain male rat show low litter sizes in the breeding colony of Wistar-Imamichi strain, and Wakafuji found a single recessive gene “SLIM”, as he called it, on an autosome cause low litter size. The colony of rats we examined was similar to theirs. The occurrence of “horn” thus appears mainly due to “SLIM”.
The data from 13 uteri, the sum of embryos of both sexes being less than 9, were excluded and each correlation was re-examined. The “horn” completely disappeared and the distribution of the sum of embryos was apparently the sum of distributions of female and male embryos both distributed normally at approximately a 1: 1 sex ratio, 7 as the means, 2.2 to 2.4 as standard deviation and -0.5 as the correlation coefficient.

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A questionnaire on animal breeding and sanitary control of facilities was conducted at 147 pet shops in Kanagawa Prefecture. The following results were obtained.
1. Eighty-two (55.8%) pet shops responded. Of those, 57 sell dogs and cats, and 25 do not. We only analysed the data of the 57 pet shops for the other 25 were inadequate. In the 57 pet shops, 35.1% sell mammals other than dogs and cats, 54.4% sell birds and 8.8%, reptiles.
2. In the 57 pet shops, 24.6% specialized in animals sales and 75.4% other forms of business such as trimming or lodging.
3. The mean number of workers, including shop owners and employee, in 57 shops was 2.6. In most (78.9%) shops, they had a license for animal treatment. A breakdown of the licensed worker, expressed by percentage of shops, was as follows : trimmers, 59.6% ; pet care advisers, 35.1% ; handlers, 14.0%; veterinarians, 8.8%; others, 8.8%.
4. The main problems of the sanitary control were that facilities could not prevent the entry of harmful insects or rats, and containers for waste matter were not adequate ; workers often did not disinfect their hands, or change clothes when they work.
5. The shops with licensed workers had sanitary facilities and better breeding animals than those without such workers. Shop owners should thus employ licenced workers to ensure high standard at pet shops.

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Annual reports on food poisoning published by the Ministry of Health and Welfare from 1952 to 1988 were used as data sources. Efficacy and availability were discussed based on the results obtained from the epidemiological statistical index of the epidemic index. The following results were obtained :
1. The epidemic index showed an L-form distribution, such as the light half of the normal distribution.
2. The epidemic index transformed to logarithmic or square root showed normal distribution.
3. Trends and seasonal variation were observed in occurrence of food poisoning by least squares method.

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