164 G. N. STEWART 



and the suprarenals in the dog, and arrives at the result that even in the 

 dog it is only a small fraction of the suprarenal store (1/12 to 1/30). 

 The whole mass of the extracapsular chromaphil tissue put together, 

 according to him, is insignificant compared with the suprarenal medulla. 

 This has an important bearing upon the question whether the suppression 

 of the epinephrin output of the suprarenals is compatible with life because 

 epinephrin is not essential, or merely because sufficient epinephrin is still 

 liberated from the extracapsular chromaphil tissue. In the opinion of the 

 writer all the evidence is in favor of the view that epinephrin is not 

 essential. Vincent (d) (1917), for instance, points out that from the rela- 

 tively large size of the chromaphil body in the dog, this animal might be 

 expected to be more resistant to extirpation of the suprarenals than other 

 animals if the chromaphil tissue were essential. But the dog does not 

 survive the operation, whereas the white rat, in which Vincent failed to 

 find any traces of "extra-suprarenal chromaphil tissue," is the most re- 

 sistant of all the laboratory animals. In the monkey, also, no chromaphil 

 bodies have been recognized with certainty. Yet the monkey is not affected 

 by interference with the epinephrin output of the suprarenals. It has 

 further been noted (Stewart and Rogoff, (u) 1920) that if the diffuse 

 chromaphil tissue is under the control of nerves in respect of any output 

 of epinephrin, as is to be supposed by analogy with the suprarenal medulla, 

 the output would be greatly interfered with by operations often practiced 

 and not incompatible with life, e.g., section of the splanchnics or appro- 

 priate section of the dorsal spinal cord, operations which also greatly inter^ 

 fere with the output of epinephrin from the suprarenals and which have 

 sometimes been successfully combined with operations for the extirpation 

 of one or (in rabbits) of both suprarenals. 



The Epinephrin Store of the Suprarenals. The quantity of epi- 

 nephrin in the suprarenals is best estimated by the colorimetric method of 

 Folin, Cannon and Denis, from the depth of the blue color given by 

 an extract with a solution of sodium phosphotungstate. Other colorimetric 

 methods have also been employed, e.g., that of Seidell(a.) (&). It can also 

 be well estimated from the rise of pressure produced by injection of known 

 amounts of an extract into a cat with the brain and the upper part of the 

 cord destroyed, according to the method of Elliott (c) (1912). Roughly 

 speaking the amount of epinephrin, expressed as base, present in the 

 suprarenals in most animals, when not placed under conditions which are 

 known to cause diminution of the store, is about one one-thousandth of the 

 moist weight of the glands. As it is confined to the medulla the propor- 

 tion in the medulla is of course much higher, in many animals at least 

 one per cent of the moist weight. According to Elliott the load is prac- 

 tically identical in each of the two glands. As was shown by Elliott in 

 the cat, if the nerves of one gland be cut and a day or two be allowed to 

 elapse to permit the store to be replenished, a deficiency in the load of the 



