56 THE SEX-COMPLEX 



Effects of thy- be no doubt that some, if not all, represent degenerated 

 ? P ars intermedia cells which have migrated into 

 the pars nervosa. There the secretion, as already 

 stated, becomes converted into a pressor substance 

 (infundibulin). 



While it is, of course, quite certain, as Herring first 

 observed and Crowe, Gushing and Homans 1 also noted, 

 that this process does occur, I have found that it is not 

 always so marked as one was led to expect. Also, in 

 contradistinction to the findings of Herring, I have 

 observed definite changes in the anterior lobe. These 

 were most marked in animals which were pregnant when 

 thyroidectomy was performed. 



The changes that occur in the anterior lobe include an 

 increase in active eosinophil cells at the expense of the 

 large basophils ; and both in the pregnant and non- 

 pregnant animal there is an increase, such as occurs 

 normally in pregnancy, of large, active chromophobe cells. 

 The latter are, however, most pronounced in an animal 

 in which thyroidectomy has been performed during 

 gestation. The condition was well seen in cat no. 3 

 of my series of thyroidectomies. Ten days after operation 

 two premature kittens were born. After a further 

 interval of 117 days the animal was destroyed. In this 

 length of time all the chromophobe ' pregnancy cells ' 

 would have disappeared in the ordinary course of events ; 

 yet, as the result of thyroidectomy, they not only 

 persisted but showed an increase in secretory activity. 

 The secretion appeared to form vacuoles among the 

 cells. In this case the pars nervosa showed no 

 abnormal invasion of pars intermedia cells. Again, 

 in the pituitary of a non-pregnant cat (no. 1), killed 

 79 days after thyroidectomy, many active chromophobe 

 cells were to be seen in the pars anterior, and an increase 

 in active eosinophil cells at the expense of the baso- 

 phils (fig. 27). In the pars nervosa there may be consider- 

 able invasion of cells from the pars intermedia (fig. 28). 



1 Crowe, S. J., H. Gushing, and J. Homans, BuU. Johns Hopk. 

 Hosp., 1910, vol. xxi, p. 127. 



