28 ANATOMY 



patches. A more satisfactory technique, described by Wis- 

 locki, 683 consists in staining with bichromate and fixing in 10 

 per cent formalin. The tissue is then washed and bleached by 

 placing in the sunlight for 6 to 24 hours in a solution of hydro- 

 gen peroxide. In this way the chromaphil tissue stands out 

 prominently against the bleached surrounding tissue. Wis- 

 locki was able to demonstrate abdominal chromaphil tissue in 

 the dog, cat, rabbit, and man, as described by earlier workers, 

 as well as in the opossum, guinea-pig, squirrel, and monkey. 

 In the rat no abdominal chromaphil tissue could be demon- 

 strated. 



Biedl and Wiesel 57 demonstrated the pressor effects of 

 extracts of the organs of Zuckerhandl to be similar to those 

 obtained from epinephrine. Vincent, 648 Fulk and MacLeod 209 , 

 and Kahn 344 showed that the accessory chromaphil tissue of the 

 dog, guinea-pig, rat, and other animals also manifested bio- 

 logical effects similar to epinephrine. Kahn showed that the 

 abdominal chromaphil body possesses about one-twelfth to 

 one-thirtieth as much epinephrine as the adrenal medulla. 

 Kahn also claimed to have demonstrated the presence of epineph- 

 rine in the venous blood draining the paraganglia, but the 

 method which he used is open to criticism. 



There is no evidence to indicate that the accessory chroma- 

 phil tissue takes over the function of the adrenal medulla when 

 the latter is extirpated. Wislocki and Crowe 685 removed one 

 adrenal from dogs, together with one-fourth to three-fourths 

 of the remaining gland, and implanted radium emanations 

 into the remaining fragments. In this way, all medullary tissue 

 was destroyed. Hypertrophy of the abdominal chromaphil 

 bodies did not occur following the operation. 



EMBRYOLOGY 



The primordial cells which give rise to the adrenals are 

 differentiated at an early stage of embryonic life. 674 The 

 medulla and the chromaphil tissue in general, and the sympa- 

 thetic nerve cells arise in common from the neural crest and 



