The effects of semi-spaying and of semi-castration on the sex ratio of the albino rat (Mus norvegicus albinus) / Helen Dean King.

  • King, Helen Dean, 1869-1955.
Date:
1911
Catalogue details

Licence: In copyright

Credit: The effects of semi-spaying and of semi-castration on the sex ratio of the albino rat (Mus norvegicus albinus) / Helen Dean King. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    The five litters produced by the two rats that were spayed on the left side contained 25 young, of which thirteen were males and twelve were females. These results show that the sex ratio is not affected in the slightest degree by the removal of the right or of the left ovary from the breeding females, and that each ovary pro- duces, in approximately equal numbers, eggs that are capable of developing into males and eggs that can develop into females. Henke and von Seligson maintain that it is not possible for a male to be produced when the right gonads are lacking in the breeding pair, or for a female to develop when the left gonads have been removed. They also state that it is impossible to fertilize the eggs of an ovary with spermatozoa from the testicle on the Table 1 FEMALE NUMBER NUMBER OF LITTERS NUMBER OF YOUNG AVERAGE NUMBER YOUNG PER LITTER MALES FEMALES 1 (R) 3 12 4.0 4 8 2 (R) 2 10 5.0 5 5 3 (L) 3 16 5.3 10 6 4 (L) 2 9 4.5 3 6 10 47 4.7 22 25 opposite side of the body. To test the truth of these hypotheses for the albino rat the following series of experiments was made: 1. Female no. 2, which had been spayed on the right side, was mated with a male from which the right testicle had been removed. A litter containing five young was obtained; three of these indi- viduals were males and two of them were females. 2. Female no. 3, spayed on the left side, was mated with a male castrated on the left side. There was one male and one female in the resultant litter. 3. Female no. 1, lacking the right ovary, was mated with a male that had been castrated on the left side. This female had a litter containing five young, of which three were males and two were females.