72 



cells do really contain the same active substance as the medulla of 

 the suprarenal capsule. It has merely been shewn that they contain 

 the same chromogen. The physiological test, even if sufficient material 

 could be collected, would probably give negative results, because the 

 material would necessarily contain so much nervous tissue, which would 

 be active in an opposite sense — i. e. would tend to lower blood- 

 pressure (Osborne and Vincent, loc. cit.). In the case of the sym- 

 pathetic ganglia this has actually been found to be the case. 

 A. Cleghorn^) finds that glycerine and saline extracts of sympathetic 

 ganglia produce a fall of blood-pressure, in spite of the presence in 

 these ganglia of some cells of the chromogenic variety like those in 

 the medulla of the suprarenal 2). 



A further point in regard to the nature of the medulla of the 

 mammalian suprarenal requires emphasising. In the adult this is no 

 longer a mass of chromogenic cells, of irregular shape and indefinite 

 arrangement, but an organ arranged in definite columns of cells with 

 intervening blood-sinuses, in fact, a "gl and" 2). The cells still 

 stain brown with bichromate of potassium, but they have to a large 

 extent lost their intimate relation to the sympathetic (see. 31). 



It is thus extremely probable that the medulla of the suprarenal 

 capsule is constantly secreting into the blood-stream an active material, 

 which serves to produce certain beneficial effects upon the muscular 

 tissues of the body (18 and 20). It has been stated by Cybulski (7) 

 and confirmed by Langlois (13) and Biedl (5) that the blood of the 

 suprarenal vein contains a sufficient amount of the active principle 

 of suprarenal extract to produce marked rise of blood-pressure when 

 intravenously injected ^). 



The above arguments all support the views I have previously (31) 

 expressed: — 



1) The suprarenal capsule in Vertebrates is made 

 up of two separate and distinct glands — the cortex and 

 the medulla. 



2) The two constituents shew a progressive deve- 

 lopment as we ascend the Vertebrate scale, the 



1) Amer. Journ. Physiol. Vol. 2, 1899, p. 471. 



2) Cleghorn did not ascertain that this result might be obtained 

 from any nervous tissue, whether brain, spinal-cord, or peripheral nerve. 

 In fact he states that this it not the case. 



3) KoHN would restrict the term gland to "epithelial" structures, 

 but he does not give a precise definition of the term "epithelial". 



4) Schäfer has, however, been unable to verify this (20). 



