316 S. Vincent, 



by chemical means, i. e., these bodies contain the same characteristic 

 chromogen as the medulla in higher animals. 



The cortex in the higher orders corresponds to the interrenal 

 body m Elasmohranch Fishes. The physiological and chemical evi- 

 dence is negative, but the histological and morphological evidence is 

 very convincing. 



7. In Teleostean Fishes the Jcnoivn suprarencd bodies (^'corjiuscles 

 of Stannius") consist solely of cortex. This is shown by the absence 

 of a physiologically active principle, by the absence of a characteristic 

 chromogen, by the fact that extirpation does not cause death [122] 

 and by their histological structure. They are thus homologous with 

 the interrenal body of Elasmobranchs. 



8. In Ganoids the same is probably true, but I am guided here 

 entirely by histological evidence. 



9. In Mammals the cortex and medulla, although anatomically 

 united into one organ, are still quite distinguishable from each other. 

 This distinction betiueen the two is not arbitrary, but rigorously marked 

 out by a layer of connective tissue (in some animals), by staining 

 reaction, and by the arrangement of the alveoli, and the shape of the 

 constituent cells. 



The medullary cells not only stain deep brown with potassium 

 bichromate, but the protoplasm stains as if it were a nucleus with 

 most nuclear stains while it stains less deeply with ordinary proto- 

 plasmic stains. 



10. The totally distinct origin and structure of cortex and me- 

 dulla renders it probable that their functioîis have no relation to 

 each other. No one would imagine that the functions of the paired 

 suprarenals in Elasmobranchs have any relation to those of the inter- 

 renal, and since the two organs seem to be only as it were accidentally 

 combined, their functions have most likely remained distinct. The 

 function of medulla would appear to be, so far as we know at present, 

 to manufacture an internal secretion which it pours into the blood 

 and which, being distributed throughout the body, maintains the normal 

 tone of the muscular structures (Oliver and Schäfer [87'\). 



As for the function of the cortex, little can be said at present 



