760 FREDERICK S. HAMMETT 



specific active principles of the posterior lobe. Hamburger (a) (&) (1910) 

 has shown,that anterior lobe extracts are depressor in action and it may 

 be that the posterior lobe extracts exhibiting a depressor effect contain a 

 preponderance of the imtransformed depressor precursor of the pressor 

 principle. Such a hypothesis of the derivation of the various effective 

 substances of posterior lobe extracts from one compound would not negate 

 the production of specifically acting compounds representing either differ- 

 ent types or different degrees of transformation of the original mother 

 substance. 



Effects on Kidneys. The response of kidney function to the adminis- 

 tration of extracts of the posterior lobe of the hypophysis is of great phar- 

 macological and therapeutic importance. From the records of the reported 

 experiments it appears as if two apparently opposed sets of reactions may 

 occur and as yet no definite indication of the factors underlying the dif- 

 ferences in response is evident. That such extracts induce an increased 

 kidney activity as expressed in an increased flow of urine has been dem- 

 onstrated by Magnus and Schafer (1901-02), Schafer and Herring 

 (1906), Thaon(e) (1010), King and Stoland (1913-14), Hoskins and 

 Means (1912-13) and others. E"ot only have diuretic effects been obtained 

 but antidiuresis has also been shown to occur as a result of injections of 

 these extracts. Pent im alii and Quercia (1912), Frey and Kumpiess 

 (1913-14), Gamier and Schulman(a) (&) (1914), Von Meyenberg (1916), 

 Motzfeldt(a)(fr) (1916) and Rees (1918) have obtained a diminution of 

 urinary output under such conditions. The only present indication of a 

 possible cause of these differences in results lies in the apparently unnoticed 

 observations of Magnus and Schafer (1901-02) that when they injected the 

 depressor compound as separated from the hypophyseal extracts by Schafer 

 and Vincent (1899) a restriction of urinary flow was obtained instead of a 

 diuresis. A study of the literature also reveals the fact that the greater 

 number of those workers reporting a diuretic effect administered the 

 extracts by the intravenous route, while those who reported an antidiuretic 

 effect administered the drug by subcutaneous or intramuscular injections. 

 It may hence be possible that the latter mode of giving the extract results 

 in the destruction of the pressor and diuresis producing substances while 

 the depressor and antidiuretic compounds are more resistant and hence 

 effective. 



The question of the nature of the action of the posterior lobe extracts 

 when diuresis is produced has aroused some considerable controversy. The 

 earlier investigators, Magnus and Schafer (1901-02) and Schafer and 

 Herring (1906) were inclined to attribute the effect to a direct stimu- 

 lative action of the drug on the renal epithelium. This conception is 

 supported by the studies of Hoskins and Means (1912-13) who showed 

 that no constant relation existed between pulse pressure, systolic pressure 

 and the diuresis, and that the most common condition accompanying 



