EXPERIMENTS OK SEX DETERMINATION. 433 



28. Experiments on Sex Detei'minatiou. 

 By Lt.-Col. S. MoNCKTON Copeman, M.D., F.K.S., F.Z.S. 



[Received October 21, 1919 : Read November 18, 1919.] 



The experimental work forming the basis of the present 

 comnuniication was carried out at intervals, as opportunity 

 served, during the years 1902-1905. But although the main 

 outcome of the Avork was demonstrated (with the aid of lantern- 

 slides) to the Physiological Society in Ma}^ 1908, and at the 

 Dublin meeting of the British Association in September 1908, 

 no account of it has previously been published. The reason for 

 this omission is to be ex^^lained by the unfortunate fact that the 

 collection of diagrams and other records, which was handed over 

 by the writer, for purposes of criticism, shortly after the research 

 came to an end, has only recently been recovered. 



From the earliest ages various writers have suggested the 

 possiljility that the reproductive glands, male or female, or both, 

 were concerned in the production of offspring of one or tlie other 

 sex. The most prevalent idea would seem to have been that the 

 glands of one side of the body gave rise to male-producing 

 spermatozoa or ova i-espectively, and vice versa. tSome observers, 

 among the most recent of whom Dr. Rumley Dawson should be 

 mentioned, have favoured the supposition that the male or the 

 female gland only was concerned ; while others have elaborated 

 the necessity for inter-action of spermatozoa and ova produced 

 by the reproductive glands of the same, or of opposite sides of 

 the body. 



In tlie hope of definitelj^ determining whether or not any of 

 these suggestions could be shown to possess basis of scientilic 

 fact, a series of experiments were devised which were carried out 

 on a somewhat extensive scale. The animals employed foi' the 

 purpose of these experiments were, for the most part, rabbits, 

 although use was also made, to a smaller extent, of pigs, cats, 

 guinea-pigs, and mice. Of these animals the greater number 

 were semi-castrated, or semi-spayed (according to sex), and 

 .subsequently kept under observation until such time as they 

 had completely recovered from the operation. An additional 

 number of animals which had already been operated on in this 

 fashion were obtained from dealers and breeders. In a later 

 series of experiments, with the object of avoiding possible fallacy 

 from the loss of an internal secretion, ligature in two places of 

 the uterine cornu, or of the cord (subsequently of the vtis 

 deferens only), on one side of the body, with partial or complete 

 section of the tissues between the ligatures in order to prevent 

 possible regeneration, was substituted for ablation of the ovaiy 

 or testicle respectively. 



Ultimately the experimental animals were bred : — 

 (a) with entire animals of the opposite sex, 

 (l>) with other semi-castrated, or semi-spayed individuals, 



