378 B. F. KINGSBURY 



tendency in its ontogeny. In connection with the last view, 

 its development as an expression of the growth of the entire 

 prechordal region requires investigation. 



The morphological significance of the suprarenal body is 

 equally obscure. However, while there are, as far as I have 

 been able to ascertain, no facts available that give any suggestion 

 as to why the cortex (or interrenal system) arises from the 

 coelomic epithelium and in a place medial to the gonadal anlage, 

 the derivation of the medulla cells from the embryonic sym- 

 pathetic system affords a basis fo"r further analysis and investi- 

 gation of the suggestion that they are, essentially and primarily, 

 undifferentiated sympathetic neurones. The type of cell is 

 widely distributed in the sympathetic system, and is character- 

 ized by its strong reducing power, which is responsible, for its 

 ready impregnation with oxydizing salts such as chromates 

 (and dichromates) , potassium permanganate, osmium tetroxid 

 etc., and is responsible for the incorrect (Kingsbury '11) and 

 misleading names of chromaffin cell, system and reaction, so 

 commonly employed. It is quite in accord with this mode of 

 origin that the suprarenal medulla cells contain a chemical 

 substance possessing the same general effect as that of the 

 neuronal system from which they were derived. 



It is also premature to attempt an explanation of the genetic 

 significance of the islands of Langerhans of the pancreas. We 

 know only that they arise out of the same anlage as the rest of 

 the pancreas parenchyma and still retain a connection with the 

 epithelium of the duct system by cell cords (Bensley '11); but 

 whether they represent undeveloped acini, regressive acini, 

 or 'exhausted' acini, and what the conditions that determined — 

 or determine — their appearance, cannot be surmised. The 

 ancestral history of the pancreas is itself obscure. 



As to the ovary (aside from the corpora lutea) and testis, 

 there is, I believe, no evidence of the existence in either of them 

 of endocrine glands, in the morphological sense, nor sufficient 

 evidence of a specific gland, in the physiological sense. To the 

 so-called interstitial cells in both instances is usually ascribed 

 the importance of a gland. In the case of the ovary I have my- 



