282 The Comparative Chemistry of the Suprarenal Capsules. 



Thirteen perfectly fresh, medium-sized specimens of Scyllium 

 canicula were dissected, and the paired suprarenals and the inter- 

 renals carefully removed. The paired bodies were all picked out 

 first, and then knife and forceps were changed for the removal of the 

 inter-renal, so as to avoid the possibility of contamination by their 

 means. 



The paired suprarenal bodies were found to weigh in a moist state 

 0*7 gram, while the inter-renals obtained amounted to 0"33 gram. 



Each of these was boiled in water for a short time, and allowed to 

 stand for about a quarter of an hour to allow time for complete extrac- 

 tion. The decoctions were made up to a strength of 10 per cent, of 

 the moist glands. Afte:- filtering, the extract obtained from the paired 

 suprarenals was of a pale brownish-pink colour with a distinct fluor- 

 escence, while that from the inter-renals was much paler, being light 

 yellow and devoid of fluorescence. 



On testing these two solutions, it was found that : — 



1. Ferric chloride gave a deep green coloration with the decoction 

 from the paired suprarenals, while no change was produced in the 

 case of the inter-renal extract. 



2. Iodine water, when added to the solution obtained from the 

 paired bodies, produced a decided pink colour, while it effected no 

 change in the tint of the inter- renal fluid. 



3. Hydrogen peroxide gave a pink coloration in the case of the 

 paired bodies only. 



4. Caustic potash gave with the paired suprarenal extract an 

 immediate dirty brown colour, but if a drop of weak hydrochloric 

 acid had been previously added, a pink coloration immediately 

 ensued. This reagent gave no effect in the case of the inter-renal. 



5. Potassium chromate produced a deep brown coloration with the 

 decoction obtained from the paired bodies,* but gave no change in 

 thait from the inter-renal gland. 



6. Silver nitrate gave a white precipitate which immediately 

 became black with the decoction of the paired bodies, but no effect 

 with that of the inter-renals. 



7. Phospho-molybdic acid gave, in the case of the paired bodies, a 

 yellow precipitate which, as well as the solution, turned green from 

 reduction, gradually in the cold, more rapidly on warming. This 

 reaction was not obtained in the case of the inter-renals. 



These reactions prove conclusively that a chromogen having the 

 same chemical nature as that found in mammalian medulla is found 

 in the paired segmental suprarenal bodies of Elasmobranch fishes. 



* This deep brown colour with salts of chromic acid has been employed to display 

 the medullary glands for purposes of dissection. It is a convenient means of 

 picking out medulla from cortex in those animals in which the two are united into 

 one organ, 



