x THE NUCLEO-PROTEIDS .455 



investigated by Miescher 1 and Ma thews, 2 according to whom they 

 contain neither protamin nor histone, but another albumin. The 

 proteid contains, according to Miescher, 2 '3 2 per cent P and T17 per 

 cent S. Miescher prepared from it a nuclein with 4*73 per cent P 

 and 1*74 per cent S, and, further, a nucleic acid, the composition 

 of which has been given on p. 442. The spermatozoa of the boar 

 are similar to those of the ox. 



2. Nudeo-Proteids of the Thymus and Nucleo-Histone 



Lilienfeld 3 obtained by collation a large number of leucocytes 

 from the thymus of the calf, which he then extracted with water. 

 By precipitating the watery extract with acetic acid he obtained the 

 ' nucleo-histone,' which amounts to 77 per cent of the dried leuco- 

 cytes. It is soluble in water, alkalies, and alkaline carbonates ; it 

 is precipitated by dilute acetic acid. Lilienfeld considers it to be an 

 acid salt of nuclein with histone. On being treated with 0'8 per cent 

 hydrochloric acid it gives rise to histone, which has already been 

 described on p. 410, and to a nuclein, the 'leuco- nuclein.' This 

 nuclein contains 4*702 per cent of P. When it is boiled or digested 

 with pepsin-hydrochloric acid it also gives rise to nucleins, which 

 contain 4*99 per cent of P. Subsequently this question has been 

 reinvestigated by Malengreau, 4 Huiskamp, 5 and Bang, 6 who have 

 arrived at the conclusion that there are present in the leucocytes of 

 the thymus two different nucleo-proteids, which differ from one 

 another in their solubilities, and particularly in their P contents. The 

 contradictory statements of the older observers 7 may be explained by 

 this fact. According to Huiskamp the thymus contains 



(a) A nucleo-histone having the percentage-composition 

 C 48-8 H 7-03 N 18-37 S 0-51 P 3'7 



It is precipitated by O'l to 0'5 per cent CaCl 2 or 0'9 per cent 

 NaCl, but it remains in solution if these salts are either in lower or 

 in higher concentration than those just mentioned. The precipitation 

 limits for ammonium sulphate are 5 '6 and 7 '2. Owing to the 



1 F. Miescher, Verhandl. d. naturforsch. Gesellsch. in Basel, 6. 138 (1874). 



2 A. Mathews, Zeitschr. f. physiol. Chem. 23. 399 (1897). 



3 L. Lilienfeld, ibid. 18. 473 (1893). 



4 F. Malengreau, La Cellule, 17. 339 (1900). 



5 W. Huiskamp, Zeitschr. /. physiol. Chem. 32. 145 (1901) ; 34. 32 (1901). 



6 J. Bang, Hofmeister's Beitrage, 4. 115 and 331, 362 (1904) ; 5. 317 (1904). 



7 J. Bang, Zeitschr. f. physiol. Chem. 3O. 508 (1900) ; 31. 407 (1900) ; A. Kossel, 

 ibid. 30. 520 (1900). 



