1910.] The Chromaphil Tissues and the Adrenal Medulla. 513 



fig. 5, col. c). In this case the cells are columnar in shape, and may] reach 

 a length of 26 fi, and the nuclei are placed at the end of the cell remote from 

 the blood-vessel. 



The protoplasm of the adrenal medulla is more distinctly granular than 

 that of the abdominal chromaphil body, and is, moreover, more delicate in 

 consistence, and therefore shows more shrinkage in fixation and tearing during- 

 the process of cutting sections. When the adrenal is fixed in bichromate 

 solutions, the section shows vacuoles similar to those described above in the 

 chromaphil body. These are absent in sublimate and Flemniing preparations. 

 Thus it seems justifiable to regard the medulla of the adrenal body as 

 composed of chromaphil cells of the same general character as those forming- 

 the chromaphil bodies. But the former have undergone specialisation, and 

 the structure of the substance has become elaborated into an organ with 

 more definitely glandular form. 



VI. The Question as to the Secretory Activity of the Chromaphil Tissues. 

 It is clear from all that has gone before that the extra-adrenal chromaphil 

 tissues contain a siibstance which gives the same macro- and micro-chemical 

 reactions as adrenin. It has been shown by Biedl and Wiesel* that the 

 " parasomata " (Nebenkorper) discovered by Zuckerkandl in the human 

 subject contain adrenin or some substance which has an identical effect upon 

 the blood-pressure. I have recently been able to prove that the abdominal 

 chromaphil bodies of the dog contain the same or a similar substance. Text- 

 fig. 12 shows the effect of injecting into the saphenous vein of a dog an 



Text-fig. 12. — Dog, 8 kilogrammes. November 10, 1909. CHCI3, morphia, atropine. 

 Carotid blood-pressure. Time in seconds. At the point signalled an extract from 

 the chromaphil bodies of three dogs -was injected into the saphenous vein. 



■* 'Arch. f. d. ges. Physiol.,' 1902, Bd. 91. 



