328 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



are found, while in non-hybridizable forms the results are not so good. 

 Pheasant and chicken give steironoth hybrids; skin transplanted from the 

 former to the latter species shows mitoses after fourteen days. In skin trans- 

 planted from chicken to pigeon, which are non-hybridizable, mitoses may be 

 found after twelve days. After transplantation of skin from the domestic to 

 the musk duck, which are likewise non-hybridizable, necrosis is found from 

 the eleventh day on. 



Exchange of skin between hybrids of Pharaniamus and another species 

 gives good results, the skin remaining alive for twenty-eight days, while skin 

 transplanted from such a hybrid to one of the parents was found living after 

 eighteen days. However, in these transplantations the exact relationship be- 

 tween donor and host was not definitely known; the hybrids may have been 

 brothers and sisters and therefore Schultz may actually have carried out 

 syngenesiotransplantations in exchanging pieces of skin between them. 



III. Experiments in Mammals. After transplantation from rabbit to hare, 

 which are hybridizable, skin was found preserved after thirty-five days, but 

 grafts from a wild to a domestic rabbit were necrotic after thirty days. Skin 

 of cat transplanted to rabbit was still alive and showed mitoses after eleven 

 days ; the beginning of necrosis was observed after fourteen days. But skin 

 of rat transplanted to mouse and the reciprocal graft showed necrosis from 

 the eleventh day on and there was marked lymphocytic reaction. 



In case of transplantation of skin from one variety to another belonging 

 to the same species, the results were good. Thus, after transplantation from 

 albino to hooded rat the graft was found preserved after thirty days and 

 showed mitoses at that time. Similarly, when skin from an albino Angora 

 rabbit was transplanted to a French grey rabhit, the results were satisfactory. 



However, the findings of Schultz, that transplants between different varie- 

 ties, such as those mentioned in the case of the rat, behave exactly like 

 ordinary homoiotransplants within the same species, do not quite agree with 

 our own. Furthermore, Schultz (1915) assumed that no differences existed 

 in the results of auto- and homoiotransplantation of skin, although marked 

 differences between these two types of transplantation had already been well 

 established. 



In addition, Schultz carried out transplantations also of ovaries. Previ- 

 ously, he had found that within the same species (rabbits or guinea pigs) 

 ovaries can be transplanted to males as well as to females. In the former, they 

 remain alive for at least four months and he concluded therefore that trans- 

 plantations between different sexes are less injurious than those between 

 different species. Furthermore, the exchange of ovaries between different 

 varieties is successful ; thus, ovaries transplanted from one variety of guinea 

 pigs to another may survive for longer than one hundred and fifty-eight days. 

 However, regeneration of ovarian tissue takes place only after homoiotrans- 

 plantation. He believes that ova, follicles, and other ovarian structures behave 

 after transplantation in a parallel way, and assumes, therefore, that the same 

 factors dominate the fate of the germ cells and of the surrounding ovarian 

 tissue. After heterotransplantation the results were unfavorable, even in nearly 

 related species; exchange of ovaries between dog and fox soon led to the 



