i INTERNAL PEOTECTIVE SECRETIONS 53 



produces no ill -effects. If one capsule is wholly, the other 

 partially, excised, it is sometimes found that a minute vestige of 

 the organ suffices to keep the animal alive, while in other cases 

 death supervenes, although a comparatively large portion of the 

 organ may remain. Histological examination shows that in the 

 first case medullary substance has been left, in the second it has 

 perished. The specific function must, therefore, lie in the 

 medullary substance. 



Another experimental proof of the great importance of the 

 medullary substance appears from the results of grafting the 

 suprarenal bodies. Animals subjected to bilateral ablation of both 

 capsules die, even if other suprarenals are grafted in their bodies, 

 and become attached. Now, while the cortical substance is 

 capable of regenerating and becoming rooted in the region into 

 which the organ is transplanted, the medullary substance does not 

 survive and degenerates completely (Poll, H. and A. Christiani). 

 According to Vassale the chromaffine tissue is fundamentally 

 altered, and loses its capacity of increasing in size by hyperplasia 

 of its own cells, when, owing to the partial ablation of tissue, the 

 remainder is forced into functional hyperactivity. The phenomena 

 of compensatory hypertrophia with cellular hyperplasia, observed 

 by Stilling (1889), and Wiesel (1899), in the surviving capsule, 

 or the accessory suprarenal bodies, after the extirpation of one or 

 both suprarenal capsules, involve only the cortical and not the 

 medullary cells. Landau (1898) again found in his experiments 

 on transplantation of the capsule and unilateral capsulectomy that 

 the taking of the graft in the first case, and the hypertrophy in the 

 second, are always limited to the cortical substance, and never 

 involve the medullary. 



From these experiments the theory of the heterogeneous 

 nature and double function of the cortical and medullary substance, 

 and of the preponderating importance of the latter, seems well- 

 established. Certain objections, however, may be raised, and have 

 to be met before the question can be regarded as settled. Kohn 

 (1903), makes the following criticisms : 



The rare cases in which the bilateral ablation of the suprarenal 

 bodies was not followed by death, were explained by invoking the 

 vicarious action of accessory suprarenals remaining uninjured in 

 the body of the animal (Stilling, 1887). These accessory organs, 

 however, shew no trace of chromaffine tissue. On the other hand, 

 some mammals, e.g. cat and rabbit, in which extirpation of the 

 suprarenal bodies is followed by death, possess in addition to these 

 organs, conspicuous masses of chromaffine tissue, e.g. on the ventral 

 surface of the abdominal aorta. Why, he asks, are these masses 

 not capable of saving the animal from death, since a minute vestige 

 of medullary substance is able to do so ? The results which 

 Abelous and Langlois obtained from amphibia agree still less with 



