40 THE SEX-COMPLEX 



Comparison a cycle of events to be demonstrated in the hypophysis 

 coUofdai according to the needs of the moment. It is probable, 



tne r th° n, d f then ' tliat the baso P nil colloid found in the rabbit's 



and the thyroid after oophorectomy represents a storage secre- 



pi ui ary. tion, wn ich is formed to meet the altered conditions of 



metabolism, but which is not of a great degree of 



physiological activity in this order of mammals. 



Reason of As we have previously suggested 1 , the inactive 



oTtto tayroid thyroid which is found in rodents is probably related to 



m rodents. th e V ery remarkable development of the interstitial 



cells in the ovaries of these animals. In consequence 



of this a marked change is produced in the thyroid of 



rodents by oophorectomy, and not to the same degree 



in other mammals, such as the carnivora. Moreover, 



thyroidectomy is comparatively harmless in rodents. 



Some haye argued, however, that the distance of the 



parathyroids from the thyroid in herbivora prevents 



their removal at the operation, and that the effects 



produced in carnivora by thyroidectomy are due to the 



removal of the parathyroids (see p. 50). This is not 



necessarily so, for I have been able to keep alive a cat 



with myx oedema for over a year. 



McCarrison 2 and others, however, have pointed out 

 that the thyroids of animals of the same species kept 

 under similar conditions vary enormously. 



EFFECTS OF OOPHORECTOMY ON THE THYMUS 



Hypertrophy Calzolari 3 first stated that castration produces 



afte/o^phor- hypertrophy of the thymus. His experiments were 



ectomy. carried out on rabbits. It has, also, been noted by 



Marrassini 4 and by Gellin 5 that castration after genital 



activity has been established gives rise to enlargement 



of the thymus. No work has been done in regard to 



1 Bell, W. Blair, and P. Hick, Brit. Med. J own., 1909, vol. i, p. 655. 



2 McCarrison, R., Lancet, 1914, vol. i, p. 931. 



3 Calzolari, A., Archiv. Ital. de Biol., 1898, vol. xxx, p. 71. 



4 Marrassini, A., Archiv. Ital. de Biol., 1910, vol. liii, p. 419. 



6 Gellin, O., Zeitsch. f. Exper. Pathol, u. Therap., 1910, vol. viii, 

 p, 1, 



