52 PHYSIOLOGY CHAP. 



dogs or cats, after sixty-eight hours on an average : but if the 

 excision be effected in two or three sittings, life is prolonged by 

 about double the number of hours. Castrated cats survive the 

 longest. 



(&) Excision of both capsules is fatal to rabbits after five to 

 six days : but if a certain period intervenes between the two 

 operations, the animal may live for months without any patho- 

 logical disturbance. 



(c) Partial unilateral or bilateral excisions are compatible 

 with survival. More or less transitory or persistent symptoms of 

 functional insufficiency appear, particularly emaciation. 



(d) In the final twenty-four to forty-eight hours of survival 

 of decapsulated animals there is a characteristic lowering of 

 temperature. 



(e) During this hypothermia of collapse, injection of suprarenal 

 extract raises the temperature again, and improves the state of the 

 animal. By such injections life may be prolonged for some 

 twenty-four hours. 



(/) Suprarenal extract injected into the veins or beneath the 

 skin of normal rabbits in a given variable dose, produces death by 

 oedema and pulmonary haemorrhage. 



XIV. Till the opening of the present century the suprarenal 

 bodies (on the strength of the data above discussed) were 

 universally regarded as glands endowed with a single, specific, 

 protective function. 



But when further research in comparative anatomy and 

 embryology brought to light the important fact that the cortical 

 and medullary parts of the organ are composed of elements 

 dissimilar in nature and in origin, it became clear that the supra- 

 renals serve a double physiological function. 



In Italy Vassale was the first to take up this position. He 

 established the special importance of the medullary substance by 

 a number of experiments (in collaboration with Zanfrognini 

 1902-3) on the removal of the suprarenal capsules in the cat and 

 rabbit. With complete ablation of the medullary substance, the 

 greater part of the cortical substance being left intact, the 

 animals die with the same acute symptoms as ensue on excision of 

 the entire suprarenals. If the ablation of the medullary substance 

 is partial, and small fragments of it are left, the animals die from 

 serious functional insufficiency after 3-4 weeks, with symptoms of 

 a special cachexia (anorexia, psychical depression, asthenia, fall of 

 temperature, marked emaciation). 



Independently of Vassale, H. and A. Christiani (1902) excised 

 the suprarenal glands in rats, with the following results. With 

 bilateral excision death is rapid and invariable, whether the 

 operation be performed in one or in two sittings, even if there be 

 a year's interval between the two operations. Unilateral ablation 



