456 CHEMISTRY OF THE PROTEIDS CHAP. 



existence of this nucleo-histone, leucocytes do not dissolve in 0*9 per 

 cent NaCl solution, while they do so in pure water. This work of 

 Huiskamp is of great interest, because the dissolution of the leucocytes 

 had always been explained on physical grounds, while it depends 

 apparently on chemical grounds (Cohnheim). 1 This nucleo-histone 

 gives a strong Molisch reaction, but not those of Millon or of Adam- 

 kiewicz. The descriptions and analyses of Bang differ but little from 

 those of Huiskamp. It is possible that the nucleo-histone may have 

 mixed with it a third substance containing a yet higher amount of 

 phosphorus. 



(b) A nudeo-proteid having the percentage-composition 

 051-78 H 7-47 N 16-42 S 1-2 P 0-95 



It is neither precipitated by CaCl 2 nor by other salts, and passes, 

 therefore, into the thymus extract, made with 0'9 per cent salt-solu- 

 tion. It may be a derivative of the nucleus, and need not be derived, 

 as Bang believes, from the intermediate substance. Its precipitation 

 limits for ammonium sulphate are 3*0 and 4*5 according to Malen- 

 greau. It gives the reactions of Millon and Adamkiewicz strongly. 



Both the nucleo-histone and the nucleo-proteid form calcium salts 

 containing 1 *3 per cent of calcium ; both are dissociated by hydro- 

 chloric acid into a nuclein and a histone ; the two histones have the same 

 salting-out limits, as have the corresponding proteids. Both yield a 

 nucleic acid containing adenin and guanin (Malengreau). Both are 

 considered i by Huiskamp 2 and Pekelharing to be the precursors of 

 the fibrin-ferment. 



The nucleo-histone prepared according to Lilienfeld has been 

 found by Gamgee and Jones 3 to be dextro-rotatory : 



<XD = +37*5 



The thymus - nucleic acid is one of the best known, as it has 

 been very thoroughly investigated by Kossel. 4 Originally it was also 



1 See also Bang, Hofmeisters Beitrdge, 5. 317 (1904). 



2 W. Huiskamp and C. A. Pekelharing, Zeitschr. /. physiol. Chem. 39. 22 (1903) ; 

 W. Huiskamp, ibid. 32. 145 (1901). 



3 A. Gamgee and W. Jones, Hofineister's Beitrdge, 4. 10 (1903). 



4 A. Kossel, Arch. f. (Anat. .) Physiol. 1891, p. 181 ; 1893, p. 157 ; 1894, p. 

 194 ; A. Kossel and A. Neumann, Ber. d. deutsch. diem. Ges. 26. III. 2753 (1893) ; 27. 

 II. 2215 (1894) ; i Zeitschr. f. physiol. Chem. 22. 74 (1896); A. Neumann, Arch. f. 

 (Anat. u.) Physiol. 1898, p. 174 ; 1899, p. 552 ; S. Kostytschew, Zeitschr. f. physiol. 

 Chem. 39. 545 (1903) ; H. Plenge, ibid. 39. 190 (1903). Compare also with the account 

 given of the pyrimidin- and purin- derivatives which Kossel and Steudel were the first to 

 prepare, and mostly out of the thymo-nucleinic acid. 



