THE SUPRARENALS 239 



In the fish cortex and medulla remain separate ; in 

 amphibians they adjoin ; in mammals the cortex encloses 

 the medulla. 



Functions of the Suprarenal Glands 



Notwithstanding that the blood-supply in the mammal 

 suggests that cortex and medulla function together, the 

 wide difference in the origin of the two parts, and the fact 

 that they remain distinct in many animals, indicate that 

 the functions of the cortex and medulla are separate. 



The Cortex 



We have no definite information regarding the function 

 of the cortex. Two suggestions may be mentioned. The 

 first, based on the high content of lipoids, is that it is 

 concerned with the manufacture of lipoids to be used 

 elsewhere. The second is that the cortex plays a part in 

 connection with the development and activity of the 

 sexual organs. Enlargement of the cortex occurs during 

 pregnancy ; hypertrophy in children is constantly associated 

 with sexual precocity. 



The Medulla — Adrenalin 



From the chromaffin cells is secreted adrenalin, which has 

 the formula — 



CH3NHCH2CHOH 



OH 



OH 



Adrenahn is remarkably active physiologically. It acts 

 upon every organ endowed with sympathetic fibres in a 

 manner identical with stimulation of these fibres. Its 

 most striking effect is upon the blood-vessels, especially 



