22 CHEMISTRY OF THE PROTEIDS CHAP. 



the corresponding inactive compounds are obtained, if the albumin be 

 dissociated by means of boiling alkalies, especially if it be boiled 

 under pressure. 1 The reason for this behaviour has been discovered 

 by E. Schulze, 2 who showed that active amino-acids are raeemised by 

 being boiled with barium hydrate. Siegfried 3 has confirmed this 

 especially for arginin and lysin. According to Kutscher, 4 arginin is 

 raeemised by being boiled for a short time with concentrated sulphuric 

 acid, or by being heated for 15 to 20 minutes in an incubator to 

 210-220. As, however, mere boiling with acids also racemises a 

 larger or smaller portion of the amino-acids, the ultimate product will 

 always contain a certain percentage of raceme-bodies. 5 This fact 

 explains the discrepancies which arise in estimating the amount of 

 polarisation exhibited by some mono-amino-acids, 6 and also partly 

 explains why various observers have described several isomeric 

 leucines 7 differing from one another in their properties. 8 



E. Fischer 9 has benzolysed the inactive, synthetically prepared 

 amino-acids, and then dissociated the benzoyl-products by means of 

 strychnine, brucine, or cinchonin salts into their active components, 

 and finally prepared from these latter the pure amino-acids. He has 

 therefore accomplished the synthesis of the dissociation -products of 

 albumins. Another simple method of synthetising a-amino-acids by 

 phtalimidmalonic ester has been described by Sorensen. 10 



The rotatory power of the salts which amino-acids form with 

 acids and bases is different from that of the free amino-acids. Leucin 

 and histidin are Isevo-rotatory, but their hydrochlorides are dextro- 

 rotatory. As the salts of amino-acids undergo great hydrolysis in 

 watery solutions, their rotatory power is found to alter with the 

 amount of hydrochloric acid present, and the rotation becomes only 

 fairly constant if a large excess of hydrochloric acid be present. 11 



* l E. Schulze and E. Bosshard, Zeitschr. f. physiol. Chem. 9. 63 (1884). 



2 E. Schulze and E. Bosshard, ibid. 1O. 134 (1885). 



3 M. Siegfried, Ber. d. deutsch. chem. Ges. 24. I. 418 (1891). 



4 F. Kutscher, Zeitschr. f. physiol. Chem. 32. 476 (1901). 



5 E. Fischer, P. A. Levene, and R. H. Aders, ibid, 35. 70 (1902) ; V E. Abder- 

 halden, ibid. 37. 499 (1903) ; E. Fischer and P. Bergell, Ber. d. deutsch. chem. 

 Ges. 36. II. 2592 (1902). 



V 6 E. Schulze and E. Winterstein, Zeitschr. f. physiol. Chem. 35. 299 (1902). 



7 R. Cohn, ibid. 20. 203 (1894). 



8 E. Fischer, Ber. d. deutsch. chem. Ges. 33. II. 2370 (1900). 



9 E. Fischer, ibid. 32. II. 2451 (1899), 32. III. 3638 (1899), 33. II. 2370 (1900); 

 E. Fischer and A. Mouneyrat, ibid. 33. II. 2383 ; E. Fischer and R. Hagenbach, ibid. 

 34. III. 3764 (1901). 



10 S. P. L. Sorensen, Zeit. f. physiol. Chem. 44. 448 (1905). 



11 A. Kossel and F. Kutscher, ibid. 28. 182 (1899) ; W. Gulewitsch, ibid. 27. 178 

 and 368 (1899). 



