54 



The Endocrine Organs 



And the fact that in the human foetus and infant so large a development 

 of suprarenal cortex occurs — which is missed in the anencephalous monster 

 — seems to indicate a connexion between the development of the substances 

 formed in the cortex and those constituting the cerebral hemispheres. But 

 against this idea we have the observation of Elliott and Armour that the 

 superadded part of the suprarenal cortex in the foetus does not contain the 

 doubly refracting lipoid substances which are characteristic of the ordinary- 

 cortical cells. Nor does the doubly refracting lipoid matter occur in all 

 animals : in many species it is absent. This is the case with all adult 

 ruminants examined, although it occurs in some in the young state. 

 In both man and animals where normally present it tends to disappear in 

 various diseases; whilst during pregnancy lipoids are said to increase in 

 amount, not only in the suprarenals but in all the organs of the body. 



The cortex increases in proportion to the growth of the body more than 



the medulla. It becomes 

 augmented in size with the 

 activity of the sexual glands 

 in animals; nevertheless, 

 castration is followed by 

 its hypertrophy. There is 

 no evidence that any kind 

 of active autacoid substance 

 is produced by the cortical 

 cells, and it is probable that 

 their function is associated 

 with the building up of 

 metabolic products which 

 are to find employment in 

 other parts of the organism. 



Structure of the 

 Medulla 



Fig. 34. — Section of suprarenal at thin part of medulla. 

 Magnified 1 50 diameters. In this section as well as 

 in that shown in fig. 32 the cells of the medulla 

 are stained brown with bichromate of potassium. 

 They contrast strongly with the cells of the zona 

 reticularis of the cortex. The blood-sinuses of the 

 medulla are seen to be continuous with those of the 

 zona reticularis. 



The medulla is composed 

 of cells which have a different 

 form and structural appear- 

 ance from those of the cor- 

 tex. They are arranged in 

 what appear in section like 

 irregular anastomosing columns with large blood-spaces between. But in 

 point of fact the medulla is better described as a solid cell-mass permeated 

 by sinus-like blood-vessels (fig. 34) with the cells compactly arranged 

 between and around them. The cells of the medulla are irregularly 

 polygonal in form, but where they abut on the sinuses they often assume 

 a more columnar aspect. There can be little doubt that the materials they 

 secrete find their way directly into the blood within the blood-spaces. 



