54 PHYSIOLOGY CHAP. 



the modern view, because in these animals the quantity of extra- 

 capsular chromaffine tissue is comparatively large as compared with 

 the intra-capsular bulk of the same tissue. 



On the other hand, the experimental results of Pettit (1896) 

 and Swale Vincent (1897), on Teleosteans, give support to the 

 modern theory. They found that eels for months survived the 

 ablation of the suprarenal bodies, which in these animals consist 

 of cortical tissue only. The chromaffine tissue, which, according 

 to G-iacomini (1902), lies near the cardinal veins, escaped the 

 operation. 



In conclusion, Kohn recommends that more attention should 

 be paid in future to the amount and condition of the whole of the 

 chromaffine tissue, in the individual animals operated on. 



Vassale (1905) subsequently attempted by special experiments 

 to decide how great an importance attaches to the extra-capsular 

 chromaffine tissue. 



In kittens, extirpation of one capsule and of the abdominal 

 aortic paraganglion may determine death with the same symptoms 

 that are observed after bilateral ablation of the suprarenal bodies, 

 or the bilateral removal of their medullary substance. In the 

 adult cat the same operation does not induce rapid death ; the 

 animal succumbs after about ten weeks, during which period, 

 although it eats with great voracity, it becomes more and more 

 emaciated, and perishes of marasmus. Dogs will tolerate the 

 removal in a first operation of one capsule and the abdominal 

 aortic paraganglion, and in a second, of the half of the remaining 

 capsule ; on the other hand, they cannot bear this triple removal 

 if performed in a single sitting the animal then succumbs in 

 twenty-four hours. 



Vassale showed that in the dog and cat the extra-capsular 

 chromaffine tissue varied in amount from animal to animal in the 

 same species, and suggested on the strength of his experiments 

 that the survival of some animals after decapsulation in successive 

 sittings was to be explained by the quantity of chromaffine tissue 

 or of extra-capsular paraganglia. The satisfactory state of animals 

 operated on in one or many sittings by maximal capsulectomy, or 

 partial excision, leaving the animals enough capsule to keep them 

 alive, is due, according to Vassale, to adaptation only. Since the 

 remaining chromaffine tissue (he says) is incapable of hyperplasia, 

 although it does exhibit some functional hyperactivity, true 

 compensation of the lost functions cannot take place. 



Admitting that the cause of death in animals exposed to 

 bilateral capsulectomy is to be ascribed exclusively to the sup- 

 pression of the medullary or paragangliar substance of the supra- 

 renal bodies, we still have to define the specific functions of the 

 cortical substance. Vassale and Zanfrognini have proposed the 

 hypothesis that the destruction of this part may be associated with 



