108 THE PROTEIN SUBSTANCES. 



from the burbot, (lotahistone, EHRSTROM), and from the sea-urchin 

 (arbacin, MATHEWs) 1 . 



Sulphur has been found in those histones in which it has been tested 

 for, but they do not, at least not all, give the lead -blackening test with 

 alkali and lead acetate. They give the biuret test, but as a rule only 

 .a faint MILLON'S reaction. The goose-blood histone first studied by 

 KOSSEL gives the three following reactions: The neutral salt-free solu- 

 tion first, does not coagulate on boiling; second, gives a precipitate with 

 .ammonia which is insoluble in an excess of the precipitant ; third, gives 

 a precipitate with nitric acid which disappears on heating and reap- 

 pears on cooling. 



The different histones behave differently in these three reactions, 

 and hence they are not specific. On the other hand, all histones seem 

 to be precipitated from neutral solution by alkaloid reagents, and they 

 .also produce precipitates in protein solutions. These two reactions are 

 likewise not specific for the histones, as the protamines have a similar 

 behavior. The histones differ from the protamines by having a much 

 lower content of basic nitrogen, and also probably by always containing 

 sulphur. True proteins, as OsBORNE's 2 edestan, also give these two 

 reactions; therefore it is impossible by qualitative tests alone to identify 

 a substance as a histone with positiveness. The large content of basic 

 nitrogen and of arginine is not a sure point of difference between histones 

 and other bodies. Histone yields little more than 40 per cent basic 

 nitrogen, while a heteroproteose yields about the same, namely, 39 

 per cent. Histone yields 14-15.5 per cent arginine (gadushistone), 

 and the lotahistone only 12 per cent. The vegetable proteid excelsin 

 is rich in arginine, namely, 14.14 percent (OSBORNE and CLAPP 3 ). The 

 characteristics of the histones according to KOSSEL are the above-given 

 reactions and the high amount of hexone bases, especially arginine. 

 The arginine nitrogen amounts to about 25 per cent of the total nitrogen, 

 the lysine N = 7-8.5 per cent and the histidine N= 1.8-4. 5 per cent. No 

 proteids, with the exception of certain protamines, are known for the 

 present, which contain as much arginine and lysine as the histones. On 

 hydrolytic cleavage the histones, like other proteins, but unlike the pro- 

 tamines, yield a large number of monamino-acids. ABDERHALDEN and 

 RoNA 4 obtained from thymus histone the following: leucine 11.8, 



1 Kossel, Zeitschr. f. physiol. Chem., 8, and Sitzungbers. der Gesellsch. zur Beford. 

 d. ges. Naturwiss. zu Marburg, 1897; Kossel and Kutscher, ibid., 1900, and Zeitschr. 

 f. physiol. Chem., 31; Lawrow, ibid., 28, and Ber. d. d. chem. Gesellsch., 34; Lilienfeld, 

 Zeitschr. f. physiol. Chem., 18; Schulz, ibid., 24; Bang, ibid., 27; Ehrstrom, ibid., 

 32; Mathews, ibid., 23. 



2 Zeitschr. f. physiol. Chem., 33. 



3 Amer. Journ. of Physiol., 19. 



4 Zeitschr. f. physiol. Chem., 41. 



