558 



CHEMISTRY OF THE PROTEIDS 



CHAP. 



get rid of these admixtures, van Name, 1 Morner, 2 Sadikoff, 3 and 

 others have attempted to overcome this difficulty by treating white 

 fibrous tissue with dilute alkalies or with trypsin, which, as already 

 stated, does not attack collagen, but the results have not been quite 

 satisfactory, as the danger of altering the collagen into glutin by a 

 too vigorous manipulation is very great, especially as collagen is 

 converted by boiling water into gelatine, and the latter, if the reaction 

 be not exactly neutral, into its dissociation-products. It follows that 

 the slightest difference in the preliminary manipulation, in the duration 

 or the intensity of boiling, and in the reaction, must of necessity 

 make the final products differ from one another. Sadikoff 's 3 recent 

 publications show again that at present it is impossible to prepare 

 glutins which are chemically pure and which agree with one another 

 in all their properties. The investigation of the dissociation-products, 

 or the study of the chemical configuration of gelatine, is, however, 

 scarcely affected by these small differences, although the latter make 

 themselves felt in the analytical numbers and when studying the 

 reactions of the gelatines. 



For the reasons just stated, only a few of the analyses of gelatine 

 are given in the following figures : 



While the nitrogen-percentage is high, the carbon-content is rela- 

 tively low, and this low percentage is also the reason why gelatine 



1 W. G. van Name, Journ. of experiment. Med. 2. 117 (according to Malys 

 Jahresber.f. Tierchem. 27. 34 (1897). 



2 C. T. Morner, " Glutin, " ZeUschr. f. physiol. Chem. 28. 471 (1898); "Fisli-scales," 

 ibid. 24. 125(1897); " Cornea," ibid. 18. 213(1893); " Tracheal cartilage, " Skandinav. 

 Arch.f. Physiol. 1. 210 (1889). 



3 W. S. Sadikoff, Zeitschr. /. physiol. Chem. 39. 396 and 411 (1903). 



4 R. H. Chittenden and F. P. Solley, Journ, of Physiol. 12. 23 (1891). 



5 E. S. Faust, Arch.f. experiment. Path. u. Pharm. 41. 309 (1898). 



6 J. Scherer, Liebigs Annalen, 40. 1 (1841). 



7 S. C. v. Goudoever, ibid. 45. 62 (1843). 



