394 DERIVATIVES OF THE PROTEIN-COMPOUNDS. 



group (C n H n _ 1 O 3 ), and not only these but valeronitrile, hydrocyanic 

 acid, hydride of benzoyl, benzoic acid, and certain aldehydes, and 

 consequently precisely the same products of decomposition as the 

 protein-compounds ; it is however, distinguished from them in 

 yielding even less acetic acid than fibrin, very little benzoic acid 

 and hydride of benzoyl, but on the other hand more valerianic acid 

 than any of the protein-compounds. 



When boiled or fused with hydrated potash glutin developes 

 ammonia, and is for the most part decomposed into leucine and 

 glycine. 



Composition. Glutin has been analysed by Mulder*, Schererf* 

 and Goudoever J. They found it to contain : 



Mulder. Scherer. Goudoever. 



Carbon 50'40 .... 50'76 .... 50'00 



Hydrogen 6'64 .... 7'15 .... 672 



Nitrogen 18'34 .... 18-32 .... - 



Oxygen 24'62 .... 2377 .... 



10-000 10-000 



No chemical formula that can be depended upon, has been 

 deduced from these analyses. Mulder originally calculated 

 C 13 H 10 N 2 O 5 , and Liebig C 52 H 40 N 8 O 20 , as the most correct for- 

 mula. The calculations were for the most part based on its com- 

 binations with chlorous acid. 



Schlieper has found 0*12 to 0*145. of sulphur in glutin obtained 

 from bones and ivory. 



Preparation. In order to prepare glutin in the purest possible 

 form from common glue, (which is obtained by boiling skins, 

 tendons, &c., and the swimming-bladder of certain kinds of fish,) 

 Berzelius used to soften it in water, to expose it repeatedly to 

 strong pressure, and then to suspend it in a linen bag in cold water 

 till everything soluble in that fluid was removed. The softened 

 glutin contained in the bag is then heated to 50, when it becomes 

 perfectly fluid, and must be rapidly filtered. The albuminous and 

 mucous portions remain on the filter, while the hot solution of 

 glutin passes through, and very soon again gelatinises. 



In order to prepare glutin from bones, we must digest them 

 for a considerable time in dilute hydrochloric acid, in order to 



* Bullet, de N^erlande. T. 1, p. 23 ; Ann. d. Ch. u. Pkarni. Bd. 46, S. 

 205-207. 



t Ann. d. Ch. u. Pharm. Bd.40, S. 46-49. 

 t Ibid. Bd. 45, S.62-6?. 

 Ibid. Bd. 58, S. 379-38 J. 



