Most of the rabbits whose unilateral ovary and opposite oviduct and uterus were simultaneously removed became pregnant and had parturition. To interpret this strange fact, it must be consid-ered that the ova ovulated from an ovary move into the opposite oviduct through the abdominal cavity, though it is entirely unknown how the ovulated ova are transfered to an opposite oviduct. The results obtained in this experiment are summerized as follows:
1) Of 15 rabbits whose unilateral ovary and the opposite genital tract were removed, 11 specimens became pregnant and were subsequently delivered of litters. Of 4 rabbits which did not get pregnant after mating, 3 had tubal ova considered to be ovulated from the opposite ovary.
2) Superovulation treatment was applied to the rabbits which did not become pregnant after repeated mating, with the following results. Tubal ova were observed in 6 specimens of 16. One of those 6 rabbits had 14 fertilized normal ova in the oviduct, while the opposite ovary had 16 ovu-lation points.
3) Complete removal of the ovary, oviduct and uterus was ascertained in the autopsy. It was also ascertained that there was no regeneration of such organs.SAKUMA, Y.;

View full abstract

[in Japanese]

View full abstract

Studies were made on the transient responses of rat ovulation and vaginal smear to the reversal of the daily lighting schedules. Two kinds of lighting schedule, which were reversal each another, were used. One of the lighting schedules was normal lighting schedule, coinciding with the solar day, in which fluoresent lamps were switched on at 5 a.m. and switched off at 7 p.m. The other was artificially reversed lighting schedule in which the lamps were switched on 7 p.m. and switch-ed off at 9 a.m. These lighting schedules were consisting of 14 hrs. of light and 10 hrs. of darkness and were automatically regulated by a time switch. The vaginal smear was taken twice daily at 9 a.m. and 7 p.m. The ovulation was examined by the discovery of ovulated ova in the ampulla of the oviduct.
The rats, which were exposed to the reversed lighting schedule and confirmed the synchronization of their vaginal smear to the lighting rhythm, were transfered into the condition of the normal lighting schedule at 7 p.m. of the each stage of their estrous cycle, and the shift of the time of ovulation after the transference was examined as well as the change of the vaginal smear.
The ovulation in the normal lighting schedule and in the reversal lighting schedule respectively take place between 1 and 2 a.m. and between 3 and 5 p.m. of the following darkness of the proestrous stage. The synchronization of the vaginal smear to the normal lighting rhythm is not recognizable within 4 days after the reversal, but confirmable within 8 to 16 days in almost all rats. The synchronizaton of the ovulation, on the other hand, is more readily achieved than that of the vaginal smear, by delay of the ovulation at the rate of 1-2 hrs. per day.

View full abstract

Embryonic mortality and frequencies of malpositions of the Japanese quail were investigated. Out of 279 fertile eggs incubated in normal orientation, 24 embryos died due to malposition-II. The effect of air-hunger in determining hatching position of the quail embryo was predominant when eggs were incubated horizontally and the large-end of the egg was coated with plastic film. When axis of the egg was set 30° from horizontal plane with its small-end-up, the frequencies of malposition-II was as high as 82%. It may be concluded that effects of gravity and air-hunger to the quail embryo are different from that reported in the chicken.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract