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G. K STEWART 



then sacrificed, being in perfect health, to permit estimation of the epi- 

 nephrin output. It was found that the concentration of epinephrin in the 

 suprarenal vein blood was no more than 1 :T5, 000,000 and the output no 

 more at most than 1/10 of the normal. According to Langlois(a) about 

 1/6 to 1/11 (Whipple and Christmaii say 1/6) of the total mass of the 

 suprarenals must be left in dogs to prevent death, and according to Biedl, 

 about 1/8 in cats, dogs and rabbits. It seems certain that when cats and 

 dogs die after removal of 9/10 of the suprarenal substance, even if medulla 

 and cortex are not removed in the precise proportion in which they exist 



Fig. 24. Intestine tracings. Blood specimens from a dog in which the right 

 suprarenal had been excised and the nerves of the left cut 25 days previously. T At 28, 

 30, 32 and 34, Ringer's solution was replaced by indifferent blood, and this at 29 by 

 indifferent blood to which was added "adrenalin" to make a concentration of 

 1:500,000,000; at 31, by a specimen of suprarenal vein blood; at 33, by indifferent blood 

 to which was added "adrenalin" to make a concentration of 1:650,000,000; and at 35, 

 by indifferent blood to which was added "adrenalin" to make a concentration of 

 1*: 800,000,000. All the blood specimens were diluted with one volume Ringer's solution 

 (the "adrenalin" specimens after adding the "adrenalin"). The segment was unusually 

 sensitive. Numerous additional observations were made with this and other specimens 

 of blood from the suprarenals, but no evidence was obtained that any of them contained 

 a detectable content of epinephrin. It was calculated that the output could not have 

 been as much as 0.0000002 mgm. per kgm. per minute, i.e., not 1/1000 of the normal 

 output. (Reduced to one-half.) (After Stewart and Rogoff, Am. J. Physiol.) 



in the gland, which could only happen by chance, they do not die because 

 of deficient epinephrin liberation from the suprarenals. More than 20 per 

 cent of rabbits, indeed, and 50 per cent of rats, survive the total removal 

 of both snprarenals. The explanation commonly given is that accessory 

 suprarenals, consisting of cortical tissue, are especially liable to occur 

 in these animals. All the best evidence goes to show that it is the cortex 

 (or interrenal tissue) and not the medulla (or chromaphil tissue) of the 

 suprarenals which is indispensable to life. The cortical tissue alone under- 

 goes hyperplasia, when a deficiency is created by removal of a considerable 

 part of the tissue. Thus, when one adrenal is removal the cortex of the 

 other hypertrophies. This is especially evident in the rabbit. State- 

 ments in the literature that the chromaphil tissue may also undergo 



