648 FREDERICK S. HAMMETT 



The Thymus as a Galactagogue 



Histological evidence seems to show that the period of activity of the 

 thymus in normal individuals hardly coincides with the time of life when 

 lactation occurs. Yet Fellner observed a degree of hyperplasia in the 

 mammary glands as the result of the injection of extracts of thymus; Ott 

 and Scott (&) further showed that thymus extracts have some galactagogic 

 effect, although MacKenzie has failed to confirm this. These observations 

 raise a question as to whether the supposedly involuted thymus takes on 

 renewed or new activity during pregnancy and lactation, or whether vari- 

 ous endocrin glands extracts have the adventitious property of stimulating 

 lactation, no specific function being involved. 



The Pineal Body and Lactation 



Both Ott and Scott and MacKenzie were able to obtain an increased 

 secretion of milk as the result of the injection of extracts of the pineal 

 body into animals. These experiments are significant, in that they 

 demonstrate a possible physiological function of this tissue, which has 

 for so long been an object of speculation as to its probable field of activity, 

 but here again we can raise the question as to whether or not the galacta- 

 gogic substance is adventitiously or functionally purposeful. 



Endocrin Glands without Galactagogic Action 



The extended investigations of Schafer and MacKenzie, and Mac- 

 Kenzie working alone, have demonstrated that among the endocrin 

 products, secretin, as well as thyroid and suprarenal extracts, does not 

 induce increased lactation when administered hypodermatically. Never- 

 theless, confirmation is lacking, and more intensive experimentation might 

 well bring out significant results. 



The Mamma as an Endocrin Gland 



It was but natural that in the search for tissues presenting the char- 

 acteristics of endocrin glands attention should have been directed towards 

 the mammary gland, since not only its histological structure, but also its 

 type of functioning would indicate the possibility of the elaboration of an 

 internal secretion. 



The mamma3 have long been known to have an influence upon the other 

 female generative organs, particularly the uterus, and this relationship 

 has been attributed by Pfister and bv Temesvarv and Biichor to nerve 



