CH. XXIII.] THE SUPRA-RENAL BODIES 339 



masses of multinucleated protoplasm (fig. 316); numerous blood- 

 vessels ; and an abundance of nerve-fibres and cells. The cells are 

 very irregular in shape and size, poor in fat, and often branched ; the 

 nerves run through the cortical substance, and anastomose over the 

 medullary portion. 



The cells of the medulla are characterised by the presence of 

 certain reducing substances. One of these takes a brown stain with 

 chromic acid, and gives other colour reactions ; it is, therefore, called 

 a chromogen. Another is similar in many of its characters to jecorin, a 

 lecithin-like substance also found in the liver, spleen, and other organs. 



The immense importance of the supra-renal bodies was first in- 



e,-i':e v 



; - 



FIG. 316. Section through a portion of the medullary part of the supra-renal of%uinea-pig. The 

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

 over, reticulated. The cells are irregular and larger, clear, and free from oil globules. (S. K. 

 Alcock.) 



dicated by Addison, who, in 1855, pointed out that the disease now 

 known by his name is associated with pathological alterations of these 

 glands. This was tested experimentally by Brown-Sequard, who 

 found a few years later that removal of the supra-renals in animals is 

 invariably and rapidly fatal. The symptoms are practically the 

 same (although more acute) as those of Addison's disease, namely, 

 great muscular weakness, loss of vascular tone, and nervous prostra- 

 tion. The pigmentation (bronzing) of the skin, however, which is a 

 marked symptom in Addison's disease, is not seen in animals. The 

 experiments of Brown-Sequard attracted much attention at the time 

 they were performed, but were almost forgotten until quite recently, 

 when they were confirmed by Abelous, Langlois, Schafer, and others. 

 The effects on the muscular system are the most marked results both 

 after removal of the capsules and after injection of an extract of the 

 glands. The effect of injecting such an extract on the voluntary 



