610 VETERINARY PHYSIOLOGY 



testes and ovaries and the cells of the corpus luteum. Brown 

 granules are also often present in them. 



The cortex suprarenalis is covered by a fibrous capsule 

 which sends trabeculge inwards. Under the capsule, the cells 

 are arranged in somewhat fan-like groups to form the zona 

 glomerulosa. Deeper, they run in parallel rows at right angles 

 to the surface, and constitute the zona fasciculata. In the 

 deepest layer, the zona reticularis, their arrangement is in 

 looser and less regular columns. 



(3) Physiology. — (1) Removal. — Biedl has succeeded in 

 removing the inter-renals in selachian fishes, and he finds that 

 the animals die. In mammals it is impossible to remove this 

 tissue without also removing the chromaffin tissue of the 

 medulla suprarenalis (see p. 590). 



(2) Extracts of this tissue are without the action of extracts 

 of the medulla. Some experiments on continuous feeding in 

 young rats indicate that the growth of the testis may be 

 stinmlated. 



(3) Relation to Gonads-— The physiological significance of 

 the inter-reuals is obscure, but that they are probably of the 

 same nature as the interstitial and other ancillary cells of the 

 o-onads is indicated by (i.) their common origin with the cells 

 of the gonads ; (ii.) their close resemblance to the interstitial 

 cells ; (iii.) the fact that pieces of inter-renal tissue are 

 frequently found in close relationship to the gonads ; (iv.) the 

 fact that abnormalities of this tissue are frequently counected 

 with abnormalities of the gonads. Hypertrophy seems to be 

 associated with premature sexual development in the male and 

 with the assumption of male characters by the female, such as 

 the typical growth of hair and muscular development ; and 

 (v.) the observation that the cells of the cortex suprarenalis 

 of the guinea-pig undergo marked changes in pregnancy. 



It has been found that in infants born with the brain un- 

 developed, the cortex suprarenalis is also defective. 



Addison's Disease- — Addison described in man a condition of 

 great muscular weakness and emaciation with a curious bronzing 

 of the skin which ends fatally, and he was able to associate this 

 with destructive lesions of the suprarenals. The evidence at 

 present forthcoming as to whether this condition is due to an 

 implication of the inter-renal tissue of the cortex is inferential 



