204 PHYSIOLOGY CHAP. 



of the whole economy, of which it is not easy to specify the causes 

 or internal conditions. It is certain, however, that these phe- 

 nomena cannot depend exclusively on the nervous relations 

 between the ovaries and the other organs ; the hypothesis seems 

 then naturally very probable that to the ovary, as well as to the 

 testicles, must be attributed a special internal secretion, the 

 cessation of which at the beginning of the menopause causes the 

 symptomatic picture we have traced. It is, however, observed 

 that in women of healthy constitution these abnormal phenomena 

 are not of long duration, and disappear entirely when the 

 climacteric period is passed, probably because there are compensa- 

 tions or functional substitutions, and a new and perfect equilibrium 

 is established. 



The phenomena following spaying or ablation of the ovaries 

 in women recall perfectly those which occur at the menopause. 

 On the effects of ovariotomy in woman we have an extensive 

 literature, which has been collected and illustrated by Hegar 

 (1878) and by Kehrer (1877) in special monographs. Experiments 

 on animals have demonstrated the little importance to be 

 attached to the nervous relations between the ovary and the 

 other organs, and have consequently given prominence to the 

 doctrine of internal secretion. 



Knauer (1896) was the first to carry out transplantation of 

 the ovaries in rabbits, and to observe that by it are avoided all 

 the local and general effects which follow ovariotomy. His 

 observations were in part confirmed by Bibbert (1898), Preobras- 

 chesky (1899), Grigorieff (1897), Kubinstein (1899), and C. Foa 

 (1900-1901). 



Of the many experiments on homoplastic transplantation of 

 the adult ovaries in rabbits made by Knauer almost all gave 

 negative results, as far as their function as sexual glands was 

 concerned. However, in one ovary, three weeks after grafting, 

 he saw the strorna and follicles still well preserved. Preobras- 

 chesky also obtained from homoplastic grafting some positive 

 results. He found that the ovary preserved its follicles for a 

 long time and regenerated the specific elements, but they after- 

 wards perished and only kept their shape transiently. C. Foa, 

 however, performing homoplastic transplantation of the embryo 

 ovary to adult rabbits, observed that they took root and soon 

 attained the structure of adult and functioning ovaries ; so much 

 so that, in one case only two months after grafting, an ovary 

 removed from a rabbit two days old and transplanted in one 

 eighteen months old produced ova capable of fertilisation and 

 proceeding to pregnancy. In a second series of experiments 

 he grafted the embryo ovary, not in the normal position, but 

 in a part some distance from it, removing at the same time the 

 ovaries from the rabbit operated on. One of these rabbits 



