68 THE GELATIN FROM WHITE 



with natural collagen, by heating commercial gelatin (purified 

 by precipitation with alcohol and containing 0.61 per cent of 

 ash) to 130 C. until constant weight was attained. This 

 substance he believed to differ from the gelatin by only one 

 molecule of water. Its composition was C 50.75, H 6.47, 

 N 17.86, S and O 24.92. It contained 0.62 per cent of ash. 

 Sulphur was not determined. 



Gorup-Besanez * gives the following analysis of tendons 

 and of the gelatin prepared from them: 



Tendons. Gelatin. 



Carbon, 50.9 50.2 



Hydrogen, 7.2 6.7 



Nitrogen, 18.3 17.9 



28.5 * 



The content of sulphur in gelatin he gave as 0.56 per cent. 



Chittenden and Solley,f by an analysis of commercial gelatin, 

 purified by precipitation with alcohol, etc., obtained the 

 following results: C 49.38, H 6.81, N 17.97, S 0.71, O 25.13. 

 The ash content was 1.26 per cent. 



Hammarsten } obtained 0.665-0.747 per cent of sulphur in 

 commercial gelatin containing 1.74 per cent of ash. 



Weiske prepared gelatin or gelatoses from bone by 

 extracting with dilute hydrochloric acid and then heating the 

 residual tissue with water at 130 C. in a Papin's digester. 

 This product contained only 0.30 per cent of ash. The 

 disadvantage of extracting tissue of this kind with hydrochloric 

 acid, although unavoidable in the study of bone-collagen, is 

 apparent from his own statement that after washing the 

 softened tissue in water for four weeks it still contained 

 chlorine. From commercial gelatin, according to O. Nasse,|| 

 the inorganic salts may be removed by long-continued soaking 

 in water. In this way he was able to reduce the ash to 0.6 



* Lehrbuch d. physiol. Chem., 1878, p. 142. 



t The Primary Cleavage Products formed in the Digestion of Gelatin. 

 Journal of Physiol., vol. xii, p. 23. 



\ Zeitschr. f . physiol. Chem., Band ix, p. 305. 



Zur Chemie des Glutins. Ibid., Bd. vii, p. 460. 



U Ueber die Chemie des Glutins. Jahresbericht d. Thierchemie, 1889, p. 29 



