194 E. UHLEKHUTH 



that this phenomenon is identical as regards its causation, with the abnor- 

 mal growth of the tail of anterior lobe-fed tadpoles. In salamanders 

 (Ambystoma tigrinum) the male possesses normally a longer tail than 

 the female; upon feeding hypophysis the tail-body ratio of the female is 

 very- little if at all indeed increased over the normal value ; it is the 

 male alone that shows the abnormal increase of this ratio. It is possible 

 that in the salamanders the increase of the tail-body ratio is due to an in- 

 creased function of the testes caused by the hypophysis diet. It is well 

 to remember, in connection with these experiments, that one of the chief 

 problems involved in the mechanism of the anterior lobe-action is how 

 much of the effects described above is due to the direct influence of the 

 anterior lobe substance and how much is due to changes of other endocrin 

 glands caused by the anterior lobe hormone. In this respect the sex glands 

 and the thyroid gland deserve special consideration. 



Relation of Hypophysis to Sexual Development. The experiments of 

 Goetsch and of Marinus on feeding anterior lobe, the extirpation experi- 

 ments of Gushing and of Bell and numerous clinical data (see Gushing 

 and Falta) leave no doubt that the anterior lobe secretion if present in 

 excess causes hyperplasia of the sex organs leading to precocious develop- 

 ment of all sexual characters ; in all probability Uhlenhuth's observations 

 on the increased growth of the tail in salamanders is a similar case. The 

 assumption of an intimate interaction between hypophysis and sex glands 

 is supported also by the observation that pregnancy (Erdheim and 

 Stumme) or gonadectomy (Hatai), the latter especially in males, result 

 in an enlargement of the hypophysis and even in important histologial 

 changes of the anterior lobe. 



Interrelation of the Hypophysis and Thyroid. That an interaction 

 exists between the thyroid and the hypophysis has frequently been stated 

 since Rogowitsch demonstrated considerable histological changes in the 

 anterior lobe of the hypophysis of thyroidectomized rabbits. Rogowitsch 

 himself declared these changes to indicate hyperactivity of the gland ; the 

 same view was taken later on by Stieda and, in regard to the posterior 

 lobe, by Herring. Recently, however, Trautmann has studied the hypoph- 

 yses of thyroidectomized goats and maintains that the weight deter- 

 minations are of little value on account of the great variations of the 

 weight of the hypophysis even under normal conditions and that the 

 histological changes found in the anterior lobe of hypophysectomized goats 

 are indicative of a degeneration (colloid degeneration of the "Haupt- 

 zellen" and replacement of functional elements by connective tissue). 

 Similarly the thyroid has been found to undergo atrophy or retardation 

 of further development after hypophysectomy (Adler (a,), Rogers, Smith 

 (e), Iloskiris and Iloskins (6). From these observations an intimate inter- 

 action existing between hypophysis and thyroid seems evident. Experi- 

 mental data suggest that even a vicarious function may exist between both 



