56 ANATOMY 



monocytes, and lymphocytes after moderate degrees of injury. 

 The reticulum cells may be transformed into macrophages and 

 the endothelial cells may become phagocytic. In the human 

 adrenal the plasma cells are most common and lymphocytes 

 second in order of their frequency. After severe experimental 

 injury of the adrenal in guinea pigs, the macrophages are most 

 abundant. The infiltrated small cells noted in the adrenal 

 occur in perfectly normal animals and although they may be 

 increased in numbers in disease, their presence is not of any 

 pathological significance as some authors have assumed. 

 These cells probably serve the physiological function of re- 

 moving the debris normally resulting from degeneration of the 

 reticular cells. 301 



The areas of infiltration of leukocytes and lymphocytes ob- 

 served in the adrenals of tumor-bearing rats represent a reac- 

 tion to the necrosis occurring in the large tumors. Similar 

 infiltrations occur in other pathological conditions and are not 

 indicative of any relation of the adrenals to cancer. 412 



