114 LEO LOEB. 



consequence of the lack of proper nourishment. We may then 

 conclude that the connective tissue is more resistant to with- 

 drawal of food than the granulosa cells; and this is a conclusion 

 which is borne out by the behavior of the connective tissue under 

 other conditions. This relatively great resistance to lack of food 

 is one of the most important characteristics of the connective 

 tissue which leads to interesting consequences under normal and 

 pathological conditions. While on the whole the connective 

 tissue cells are more resistant than the "granulosa cells yet we 

 noticed that under the conditions of ill nourishment prevailing 

 under our experimental conditions, the ingrowth of connective 

 tissue into the follicular cavities was not rarely somewhat re- 

 tarded. In such cases we see the follicle forming a cyst lined by 

 theca interna in which the ovum lies free or almost free and in 

 which connective tissue has not yet grown. 



The atresia of follicles is comparable to a condition which in 

 other organs is designated as cirrhosis. In the case of the atresia 

 of follicles this cirrhotic process is a substitutive one ; the stimulus 

 which induces the connective tissue to become active consists 

 in the loss of the granulosa cells which formerly covered the 

 theca interna. As we pointed out on former occasions, we have 

 reason to assume that there exist in addition stimuli of a different 

 character w T hich call forth cirrhotic processes. 1 



From our investigations it follows that in the guinea pig 

 underfeeding prevents maturation of the follicles and thus causes 

 sterility which lasts as long as the effect of the underfeeding is 

 present in the ovary. This lack of maturation we found in 

 all our cases. In addition we found in the large majority of 

 those animals which had become more markedly affected by the 

 lack of sufficient food, especially in those which had not yet 

 reached their full size, a much farther-going deficiency in the 

 development of the follicles, a condition of the ovaries to which 

 we applied the name "hypotypical." The latter state is alto- 

 gether incompatible w r ith fertility. The problem that is as yet 

 unsolved concerns the length of time during which this condition 

 is present, and whether the ovaries resume their normal life 

 very soon after the quantity of food has again been increased, 

 or whether the hypotypical condition and lack of maturation 



1 Loeb, Leo, Journ. Amer. Med. Ass'n, 1915, LXIV., 726. 



