The Further Effects of Irradiation on the Oestrous Cycle of the Ferret

The investigation of the effect of radiation on the oestrous cycle of the female ferret has been continued. (1) The earlier experiments with the ultra-violet light have been repeated and confirmed. Irradiation with light of λ 3650Å. caused the ferrets to come on heat early and to remain on heat for an abnormally long time after irradiation had ceased. (2) Heat rays of long wave-lengths caused no acceleration. This is in accordance with earlier experiments which showed that heat rays and infra-red (λ 7500Å.) had little effect. (3) Two pairs of ferrets were subjected to the same total quantity of radiation from incandescent lamps, but in one case it was concentrated into 2 hours, and in the other spread over 16 hours. There was little difference in the behaviour of the two pairs and both showed an acceleration of oestrus.