88 THE STRUCTURE OF THE FOWL 



medial to the anterior lobe of the kidneys. 

 In mammals distinct and separate cortical 

 and medullary portions can be distinguished ; 

 but in the fowl cortical and medullary cords of 

 polyhedral cells are irregularly intermingled. 

 The cells composing the medullary cords have 

 an affinity for chromic acid and are conse- 

 quently designated chromaffin. Apparently 

 the adrenal is a dual organ with a double 

 embryonic origin. According to current views, 

 the cortical cells are derived from ingrowths 

 of the peritoneum, while the medullary cords 

 are developed from sympathetic ganglia. 



