THE ADRENAL BODIES 149 



it is always present, though in varying degree in the animals 

 ordinarily used for experiment (dog, cat, and rabbit). The 

 removal of one adrenal and the abdominal chromaphil body 

 causes death in young cats with the same symptoms as those 

 obtained after bilateral extirpation of medulla only. Vassale 

 thinks that survival of animals, when it occurs after extirpation 

 experiments, can be satisfactorily explained by the extra 

 amount of extra-adrenal chromaphi] substance which happens 

 to be present in these individuals. 



A further discussion of the question as to the relative 

 importance to life of the cortical substance and the chromaphil 

 material can only be carried on after the account of extirpation 

 experiments upon lower vertebrate animals. 



According to Biedl, the cortical accessory adrenals occur 

 very rarely in dogs and cats, in rabbits in about 15 to 20 per 

 cent, of animals examined, in rats in almost 50 per cent, of 

 cases, in guinea-pigs not more than 4 per cent, of cases. 



G. Extirpation of the Adrenals in the Lower Vertebrata 



Perhaps the best-known and most-often-quoted series of 

 extirpation experiments upon any animal is that carried out 

 upon the frog by Abelous and Langlois in 1892. This was, of 

 course, at a period before the discovery of the physiological 

 effects of adrenal extracts upon the blood-pressure. The 

 authors employed frogs because these animals, they say, do 

 not suffer from the shock of operations as do mammals, and, 

 in general, tolerate operative proceedings very well. Abelous 

 and Langlois were the first to study the physiology of the 

 adrenals in the frog. 



Destruction by means of the actual cautery was the method 

 of extirpation employed. A platinum wire brought to a red 

 heat was applied to the bodies on the anterior surface of the 

 kidneys. The authors found that male frogs are more suitable 

 for the operation than female, and summer frogs better than 

 winter frogs. There was never any post-operative shock. 



Total destruction of both capsules always led to death. 

 Immediately after the operation the animals were normal. It 

 was only after a certain period that one observed ill-effects 

 which finally caused death. The duration of survival was 

 variable. It varied according to the season ; winter frogs 



