1913] Walter H. Eddy 421 



hempen bag to remove the juice, which contained lymphocytes that 

 were separated in a centrifuge. The lymphocytes were then ex- 

 tracted with water to extract nucleohiston. (In a modification of 

 this process, the minced glands were extracted directly with water.) 

 The nucleohiston was precipitated from the extract with acetic acid, 

 and purified by re-solution in water to which a little sodium car- 

 bonate had been added and reprecipitating with acetic acid. The 

 precipitate was then treated with 0.8 per cent. hydrochloric acid 

 Solution. From this Solution of histon-hydrochloride, histon was 

 precipitated with ammonia (added either before or after dialysing 

 free from free acid). The ammonia-precipitated product was 

 finally purified by washing with alcohol and ether, and dried to 

 constant weight. 



C. Salmin histon: Miescher, 1896 {22). The nuclei of 

 unripe salmon sperm were extracted with 0.25 per cent. hydro- 

 chloric acid Solution, the extract filtered and (after dialysing to 

 neutrality) the filtrate precipitated by Saturation with ammonium 

 Sulfate or sodium chlorid. 



D. Arbacin histon: Mathews, 1897 (21). Preparation I. 

 Dried sperm heads were extracted with 1-2 per cent. sulfuric acid 

 Solution and the acid extract poured into a large volume of alcohol 

 to precipitate the histon-sulfuric acid complex. The precipitaie was 

 purified by washing with alcohol-ether and dried to constant weight. 

 Preparation II. The alcohol-precipitated product was dissolved in 

 water, the Solution made ammoniacal and filtered (no precipitate 

 at this point), the filtrate poured into alcohol, and the resulting 

 precipitate washed free from ammonia and redissolved in a small 

 volume of water. Ammonia added to this concentrated Solution 

 failed to completely precipitate the histon, which showed a strong 

 tendency to remain dissolved in ammoniacal Solutions. Matthews' 

 studies were based on the use of alcohol-precipitate from acid ex- 

 tract, alcohol-precipitate from an ammoniacal water-solution, and 

 ammoniacal water-solution neutralized with sulfuric acid. 



E. Globin histon: Schulz, 1898 (23). A Solution of hemo- 

 globin was treated with dilute hydrochloric acid Solution and a 

 brown precipitate obtained, soluble in the presence of a very slight 

 excess of acid. When this precipitate was dissolved in acid and 



