ANDROGENIC TISSUE 61 



Soon after birth involution begins, assuming a massive form 

 during the second week of life. During this period the cells 

 of the androgenic zone are found in all stages of nuclear and 

 protoplasmic degeneration. Fat droplets appear in the de- 

 generating cells which are displaced and compressed by the 

 concomitant hyperaemia and growth of the medulla which 

 occurs rapidly at this stage. Phagocytosis of red blood cells 

 with pigmentary degeneration occurs with thickening of the 

 intercellular reticulum. 182 The degenerating androgenic zone 

 is sharply marked off from the true cortical tissue which re- 

 mains intact, and from the growing medulla. 



At the end of the first year the above involutionary proces- 

 ses are almost complete and the androgenic zone is replaced 

 with connective tissue in the meshes of which may still be 

 found degenerating pigmented cells. This connective tissue 

 by compression becomes narrow and ultimately assumes the 

 layer separating the medulla from the adult cortex. 



Neither prematurity nor inanition were found by Lewis and 

 Pappenheimer 395 to affect the involution of the androgenic 

 zone, but syphilis markedly retarded its disappearance. In- 

 fection by penumonia caused an increased size of the true cor- 

 tex while the involution of the androgenic tissue continued, 

 which is evidence for the functional independence of the two 

 tissues. Lewis and Pappenheimer also showed the simulta- 

 neous disappearance of the "accessory cortical tissue" or ac- 

 cessory androgenic bodies, as we have called them, which is 

 evidence for their physiological homology with the androgenic 

 zone of the adrenal. 



The significance of the involution of the androgenic zone in 

 man has often been the subject of speculation but the theories 

 heretofore advanced to describe the phenomenon are easily re- 

 futed. The idea that it results from pressure by the growing 

 medulla was shown by Lewis and Pappenheimer 395 to be un- 

 tenable since a similar degeneration occurs in the accessory 

 bodies where there is no growth of medullary tissue. Ma- 



