28 OBGANIC CONSTITUENTS. 



The composition of glycicoll is represented by the formula' 

 C, H^ N^ Ojor C, H, N, 0^ + 2 HO. 



It is worthy of remark that on subtracting an equivalent 

 of grape or diabetic sugar from two equivalents of glycicoll^ we 

 obtain the elements of two equivalents of urea : 



2 (C, H^,N, O,) — C,, H,, O,, = 2 (C, H^ N, OJ 



The origin of glutin in the animal organism is still unknown. 

 As no traces of it have ever been discovered in the vegetable 

 kingdom, we cannot suppose that (like protein) it arises from 

 that som-ce. In all probability it is formed by the action of 

 alkalies on protein; since we know that protein, submitted to 

 sucli influences, yields products which in their chemical compo- 

 sition approximate closely to glutin, and that the blood is suffi- 

 ciently alkaline to effect such, or similar, modifications. 



In the hair, we find, associated with bisulphuret of protein 

 Pr + 2 S, a connecting tissue, G,, H,„ N, O,, which difters from 

 glutin, C,3 H,Q N^ O^, simply by one atom of nitrogen. 



Moreover protid, C,^ H^, N O^, and erythroprotid, 0,^ H^ N O^, 

 nearly resemble glutin in their composition, and both glutin and 

 the protein-compounds yield leucin when treated with caustic 

 potash. These facts render it in the highest degree probable, 

 that glutin is formed in the organism, from the decomposition 

 of protein b}^ alkalies ; much as protid and erj'throprotid are 

 produced in the laboratory. A reference to the symbolical 

 illustration in page 14, will show that with every two equiva- 

 lents of ammonia that are developed, there are produced one 

 equivalent of protid, C,^ H^ N O^, and one of erythroprotid 

 Cj3 Hg N O^. If we add to each of these the elements of one 

 equivalent of ammonia, we obtain 



C.. H,, N^ O, and C, H,, N, 0„ 



It only remains for us to assume that the oxygen which is con- 

 tinually acting on the blood in the lungs, yields three equiva- 

 lents of oxygen to the former, and one to the latter of these 

 substances, and we have from the protid, 



C,3H„,N,0, + 0, or C,3 H.^N,, 0^ + 2 HO; 



and from the erythroprotid, 



.C,,H..N,0,-hO or C,3H,,N„0^-f-H0; 



that is to say, glutin and Avater may be supposed to be formed 



' See Appendix I, Note 15. 



