122 GELATINE CONTAINS NO PROTEINK 



17. By means of these formulae we can trace the 

 production of the different compounds from the constit- 

 uents of blood ; but the explanation of their production 

 may take two forms, and we have to decide which of 

 these comes nearest to the truth. 



For the same amount of carbon, membranes and the 

 tissues which yield gelatine contain more nitrogen, oxy- 

 gen, and hydrogen, than proteine. It is conceivable, that 

 they are formed from albumen by the addition of oxygen, 

 of the elements of water, and of those of ammonia, 

 accompanied by the separation of sulphur and phos- 

 phorus ; at all events, their composition is entirely dif- 

 ferent from that of the chief constituents of blood. 



The action of caustic alkalies on the tissues yielding 

 gelatine shows, distinctly, that they no longer contain 

 proteine ; that substance cannot in any way be obtained 

 from them ; and all the products formed by the action 

 of alkalies on them differ entirely from those produced 

 by the compounds of proteine in the same circumstances. 

 Whether proteine exist, ready formed, in fibrine, albu- 

 men, and caseine, or not, it is certain that their elements, 

 under the influence of the alkali, arrange themselves so 

 as to form proteine ; but this property is wanting in the 

 elements of the tissues which yield gelatine. 



The other, and perhaps the more probable explana- 

 tion of the production of these tissues from proteine, 

 is that which makes it dependent on a separation of 

 carbon. 



If we assume the nitrogen of proteine to remain en- 

 tire in the gelatinous tissue,' then the composition of the 



