424 CONNECTIVE TISSUE IN MUSCLE. 



From the preceding considerations it is evident that the 

 material assumed by Schepilewsky to be mucin is neither 

 a glycoproteid nor a nucleoproteid. Its composition and solu- 

 bilities recall the stroma substance of J. von Holmgren.* 

 This investigator, repeating Danilewsky's experiments,! treated 

 the insoluble muscle stroma remaining after complete extrac- 

 tion of muscle with water and ammonium chloride solution, 

 with dilute alkali. He obtained in this way from horse and 

 rabbit muscle a proteid precipitable by acids and yielding 

 neither xanthin bases nor reducing substances. Von Holm- 

 gren's stroma proteid contained from 15.84 to 16.66 per cent 

 of nitrogen. 



In speaking of the final filtrate the gelatin solution 

 obtained by dissolving the connective tissue in hot alkali 

 Schepilewsky says : " It gives no coloration with Millon's 

 reagent, if the proteids have actually been removed." J It 

 has been taught quite universally that pure gelatin does not 

 give Millon's reaction ; the latter, when obtained with gelatin 

 solutions, is attributed to contaminating proteids. But the 

 investigations of Van Name || in this laboratory have demon- 

 strated that perfectly pure gelatin, prepared from connective 

 tissue, still gives a red coloration when warmed with Millon's 

 reagent; and this observation has received confirmation in 

 the recent work of C. Th. Mo'rner.^[ In order to test the 

 matter still further we have neutralized and concentrated 

 the gelatin-containing filtrates obtained by Schepilewsky's 

 method, and have precipitated the albuminoid material with 

 alcohol. The precipitate of gektin (or gelatoses) gave the 

 characteristic red coloration with Millon's reagent. 



* Von Holmgren, Jahresbericht fttr Thierchemie, 1893, xxiii, p, 360. 



t Danilewsky, Zeitschrift fiir physiologische Chemie, 1882, vii, p. 124. 



J Schepilewsky, loc. cit., p. 358. 



E. g., Neumeister, Lehrbuch der physiologischen Chemie, 1897, p. 63. 

 Salkowski, Practicum der physiologischen und pathologischen Chemie, 1900, 

 p. 199. 



|| Van Name, Journal of Experimental Medicine, 1897, ii, p. 117. 



f C. Th. Morner, Zeitschrift fiir physiologische Chemie, 1899, xxviii, p. 484. 



