422 Htston and its Preparation [April 



one-fifth its volume of alcohol and ether added, the color passed 

 into the ether leaving a clear water-alcohol Solution, from which 

 ammonia precipitated a yellowish flocculent mass of globin, that, 

 when washed free from ammonia, began to dissolve, a few drops 

 of acetic acid Solution completing the process. Dialysed free from 

 acid, a clear, neutral, slightly colored, odorless and tasteless Solution 

 of globin resulted. Schulz' tests were based on this Solution and on 

 the ammonia-precipitated product. The analyses were made on the 

 latter, washed with alcohol and ether, and dried in vaciio to constant 

 weight at a temperature of ioo° C. 



F. ScoMBRON histon: Bang, 1899 (2). Unripe mackerei 

 sperm was heated with alcohol and the residue dried. This dried 

 residue was then extracted with dilute hydrochloric acid Solution 

 and the histon precipitated from the filtrate with caustic soda, 

 ammonia, or by Saturation with sodium chlorid. The product was 

 purified by re-solution in water containing a trace of acid, reprecipi- 

 tation with the desired reagent, washing with alcohol and ether, and 

 drying to constant weight. Bang's Statement of " characteristic 

 properties " of histon was based upon the water-solution of the 

 products precipitated by sodium hydroxid or sodium chlorid. His 

 analyses were based on the ammonia-precipitated product. (See 

 pages 424 and 426. ) 



G. Para-histon: Fleroff, 1899 (9), Preparation I. 

 Minced thymus glands were treated with alcohol and ether, and the 

 residue extracted with 2 per cent. sulfuric acid Solution (100 gm. of 

 thymus to each 1,000 c.c. of acid Solution). The filtered acid ex- 

 tract was then precipitated with three volumes of alcohol, the 

 precipitate dissolved in hot water, and the Solution heated with 

 sodium picrate. The histon picrate was then reconverted into the 

 Sulfate by treatment with 2 per cent. sulfuric acid Solution and 

 ether, and reprecipitation with alcohol. This process was repeated 

 twice. The final precipitate was then dissolved in water, f reed from 

 Sulfate with barium hydroxid, and excess of barium precipitated 

 with carbon dioxid. To this turbid, viscid liquid was then added 

 an equal volume of alcohol, and ammonia, and the liquid filtered. 

 Excess of alcohol added to the filtrate precipitated para-histon. 

 This was still further purified by dissolving in water and repre- 



