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HANDBOOK OF PHYSIOLOGY. 



posure to light, and giving with ferric chloride a green or blue color. 

 Haemochromogen has been found by McMutfp. Neurin, apparently 

 from the nervous elements, has also been shown. 



Function. Though formerly unknown, a vast amount of light has 

 been thrown upon the function of the supra-renal capsules within the last 

 few years by the researches of Schafer and Oliver, Zyboulski, Abel, and 

 others. Brown-Sequard, it is true, showed by experiment as early as 

 1856 that removal of the supra-renal capsules is followed by the death of 

 the animal, but his experiments were repeated by others who did not 

 obtain the same results; and it was concluded that the supra-renal cap- 

 sules had no function, or at least that their function was not known. 

 Death was preceded in the case of Brown-Se'quard's animals by symptoms 



Fig. 226. Section through a portion of the medullary part of the supra-renal of guinea-pig, 

 ine vessels are very numerous, and the fibrous stroma more distinct than in the cortex, and is 

 moreover reticulated. The cells are irregular and larger, clean, and free from oil globules. X 

 (.. K. Alcock.) 



somewhat analogous to those of the disease of man known as Addison's 

 disease. The failures to produce symptoms after attempted removal of 

 the glands have probably resulted from incomplete removal or the pres- 

 ence of accessory bodies. Accessory supra-renal capsules are commonly 

 present in some animals and are sometimes found in man. Further, if 

 one gland is removed, the other hypertrophies. The experiments of all 

 recent observers confirm the original experiments of Brown-Sequard. 

 The presence of the supra-renal capsules is essential to life. Thus the 

 supra-renal capsules are proved to have a very important function, and 

 they perform this function through the agency of an internal secretion. 



Schafer and Oliver found that injections of supra-renal extract pro- 

 duced marked effects upon the muscular layer of the arteries, the mus- 

 cular tissue of the heart, and the skeletal muscles. The muscular layer 

 of the arteries is markedly contracted, causing a rise of blood-pressure. 



