Chemistry of the Suprarenal Capsules. 



281 



the active material.* When active suprarenal material is subjected 

 to the action of strong alcohol (98 per cent.) for seven to ten days, 

 the active material becomes destroyed, as shown by the physiological 

 test of intravenous injection, but the chromogen is unaffected, and 

 continues to give the usual colour tests in a characteristic fashion. f 

 Hence the two substances are not identical, but their close associa- 

 tion suggests the probability that the active material has a very 

 complex molecule (for only such a molecule would be destroyed by 

 prolonged contact with alcohol), and that the group giving the 

 colour reactions forms an integral part of this molecule, and is not 

 broken up in the decomposition. J 



The colour reactions referred to above are common to all ortho- 

 dihydroxy-benzene derivatives, and are briefly as follows : — 



1. Addition of various oxidising agents causes a rose-red colora- 

 tion. This can be produced by addition of bromine-, or iodine-water, 

 or solution of hydrogen peroxide, or alkalis. § 



2. Addition of ferric chloride to a neutral solution causes a deep 

 green colour. 



3. Certain metallic salts are precipitated and then reduced, e.g., 

 addition of Ag]ST0 3 causes a white precipitate which rapidly becomes 

 black from reduction, especially on warming. Similarly, phospho- 

 molybdic acid produces a yellowish precipitate, which, as well as the 

 yellow solution, rapidly turns green. 



4. Addition of potassium chromate causes a deep brown colour, 

 probably due to an admixture of the colour of the chromate with the 

 products of oxidation of the chromogen. 



Although there is no purely chemical test known which indicates 

 the presence of the physiologically active material, these colour tests 

 make it easy to demonstrate with certainty the presence of the 

 chromogen. Now, as the chromogen and the active material are 

 closely associated in the mammalian medulla, and, as it has further 

 been shown that the paired bodies of Elasmobranchs contain the 

 active material, || it appeared to us of importance to determine 

 whether the chromogen was also present in these structures. 

 Accordingly, the following experiment was performed. 



* Moore, 'Physiol. Soc. Proc.,' March, 1894 (Mourn, of Physiol.,' vol. 17, 1895, 

 p. 14). 



f This applies not only to mammalian medulla but also to the medullary 

 suprarenals of Elasmobranch fishes {vide Vincent, ' Eoy. Soc. Proc' vol. 61, 1897, 

 p. 64). 



% Moore, * Journ. of Physiol.,' vol. 21, 1897, p. 382. 



§ This rose-red colour produced by alkalis immediately and completely dis- 

 appears on making acid again, and once more returns on making alkaline; the 

 change in colour may be repeated as often as is desired. It is also intensified if the 

 suprarenal extract has previously been boiled in acid solution. 



|| Vincent, loc. cit. 



VOL, LXTI. X 



