IX 



THE HISTONES 



417 



The thymus-histone differs widely from other histories as regards 

 its properties, its high sulphur-content, and its dissociation-products, 

 which have been investigated by Kossel and Kutscher, and are given 

 on p. 74 No. 37. The high arginin- and ty rosin -con tents are 

 especially interesting. Abderhalden and Kona, 2 employing Fischer's 

 ester- method, found amongst the dissociation -products of thymo- 

 histone : glycocoll, alanin, a-pyrrolidin-carboxylic acid, phenylalanin, 

 glutaminic acid, ty rosin, and probably also aspartic acid and cystin. 

 Thymus-histone is readily digested, being even attacked by erepsin. 3 



2. Globin 



Globin is the only, or, at any rate, the most essential albumin- 

 radical of hemoglobin. It has been known for some time and was 

 given its name by Preyer, 4 but it was first prepared in a pure state by 

 Schulz, 5 and identified by him as a histone. 



Globin differs from other histones in being precipitated by a 

 specially small amount of ammonia or alkali, and also by being 

 equally readily dissolved in the slightest excess of these reagents, 

 and if the excess be at all great even in the presence of ammonia 

 salts. Schulz gives the following percentage composition : 



C 54-97 H 7-2 N 16'89 S 0'42 20'52. 



Its dissociation-products are given on p. 70, No. 1. Its high 

 bistidin- and leucin-content are worthy of notice. 



As globin is readily obtainable from haemoglobin, and as the latter 

 amongst all albumins is the one which can be prepared in the purest 

 Form, globin has often been used for experiments on digestion 6 and 

 dissociation, and excepting some of the protamins, it is the most 

 thoroughly analysed substance. According to Schulz 7 it is unusually 



1 J. Bang, Zeitschr. f.physiol. Chem. 27. 463 (1899) ; 3O. 508 (1900) ; 31. 407 

 (1900) ; Hofmeisters Beitrage, 4. 115 and 331 (1903) ; and 362 ; 5. 317 (1904). 



2 E. Abderhalden aud P. Rona, Zeitschr. f. physiol. Chem. 41. 278 (1904). 



3 0. Cohnheim, ibid. 35. 134 (1902). 



4 W. Preyer, Pfliiger's Archiv. 1. 395 (1868) ; and Die Blutkristalle, Jena, 1871. 



5 F. N. Schulz, Zeitschr. f. physiol. Chem. 24. 449 (1898). 



6 S. Salaskin and K. Kowalewsky, ibid. 38. 571 (1903). 



7 F. N. Schulz, ibid. 24. 449 (1898). 



2 E 



