356 CHEMISTRY OF THE PROTEIDS CHAP. 



Michel, 1 Giirber, 2 Starke, 3 and Sebelien. 4 Iodised serum - albumin 

 contains 12 per cent iodine, according to Kurajeff. 5 It combines with 

 1 to 0'2 grm. hydrochloric acid, according to Erb. 6 The capacity for 

 alkali for the same concentrations is, according to Spiro and Pemsel, 7 

 much less. The dissociation-products are mentioned in the table, 

 p. 70, No. 2. Glycocoll is absent, otherwise the products are the 

 usual ones. Its bases have not been investigated. Sulphur exists 

 only in the form of cystin, according to Morner. 8 Serum-albumin 

 yields some glucosamin, according to Langstein, 9 and perhaps also 

 still another carbohydrate acid, but only in infinitesimal quantities 

 (see p. 160). Dissociation by means of pepsin has been investigated by 

 Umber; 10 while that by trypsin takes place only slowly and very 

 incompletely, according to Oppenheimer and Aron, 11 probably because 

 of its antitrypsin-content (Cohnheim). 



According to Starke 3 it is only slowly denaturalised by alcohol and 

 ether, and thus differs from other albumins ; Johannsson 12 has also 

 noticed a remarkable resistance of serum-albumin towards dissociation 

 by means of dilute acids ; even 2 per cent HC1 attacks it at room- 

 temperature only after twenty-four hours, while 0*25 per cent 

 hydrochloric and 2 per cent acetic acid have no action. 



After Starke 13 had succeeded, for the first time, in converting egg- 

 albumin into a globulin by means of heat, Mott 14 has also accomplished 

 the conversion of serum-albumin over a pseudo-globulin stage into 

 euglobulin by either heating normal serum for half an hour up to 56, 

 or heating 1 to 3 per cent, of crystalline serum-albumin dissolved 



in - caustic soda solution. The more concentrated an albumin- 

 solution, the greater is the yield of the globulin. What makes the 

 investigation of Mott so important is that the artificial globulin agrees 

 with the normally occurring euglobulin not only in such physical 



1 A. Michel, Sitzungsber. der Wiirzburger phys.-med. Ges. N.F. 29. 117 (1895). 



2 A. Giirber, ibid. 29. 139 (1895). 



3 K. V. Starke, Maly's Jahresbericht, 11. 17 (1881). 



4 J. Sebelien, Zeitschr. f. physiol. C/iem. 9. 445 (1885). 

 s D. Kurajeff, ibid. 26. 462 (1899). 



6 W. Erb, Zeitschr. f. Biolog. 41. 309 (1901). 



7 K. Spiro and W. Pemsel, Zeitschr. f. physiol. Chem. 26. 231 (1898). 



8 K. A. Morner, ibid. 34. 207 (1901). 



9 L. Langstein, Hofmeisters Beitrage, 1. 259 (1901). 



10 F. Umber, Zeitschr. f. physiol. Chem, 25. 258 (1898). 



11 C. Oppenheimer and H. Aron, Hofmeisters Beitrage, 4. 279 (1903). 



12 J. E. Johannsson, Zeitschr. f. physiol. Chem. 9. 310 (1885). 



13 J. Starke, Zeitschr. f. Biol. 40. 419 and 494. 



14 L. Mott, Hofmeisters Beitrage, 4. 563 (1904). 



