430 



H ist 011 and its Preparation 



[April 



nudcoprotcin free from histon and a nucleohiston. Malengrau 

 claimed that thymus contains and yields to water, A-micleoalbiimin 

 and B-nudcoalhumin, both containing histon and the latter com- 

 parable to Bang's complex. Bang claimed that thymus contains a 

 nticleo protein, free from histon and extractable by water or 0.9 per 

 Cent, sodium chlorid, and a histon micleate. 



Commenting generally on these views, Bang held that the 

 thymus gland yields either a multitude of nuclein-containing sub- 

 stances or the nucleoprotein is changed by the various processes in- 

 volved in its Separation, or the dififerent methods of preparation 

 produce mixtures of pure and impiire substances. Bang therefore 

 considered it necessary^ to reinvestigate all methods. In brief his 

 conclusions are : Malengrau's A-nucleoalbumin is an alhuminate, 

 not a histon. It is identical with Bang and Huiskamp's nucleo- 

 protein. Huiskamp's nucleoprotein is identical with Bang's accord- 

 ing to the following percentage analytic data: 



The essential difference, therefore, lies between Bang's histon 

 nucleate theory and Huiskamp's nucleohiston theory. Bang re- 

 ported extensive studies to confirm his point of view. For com- 

 ment on these views see p. 436. 



V. EXPERIMENTAL 



I. The cause of the water-insolubility of ammonia-pre- 

 cipitated histon. A. Comparison of ammonia and sodium 

 CHLORiD-PRECiPiTATED HISTON. Many preparations of thymus 

 histon were made involving variations in the process and the use of 

 many different sets of glands from calves. All the glands used 

 were, with one exception, obtained immediately after slaughtering 

 and were extracted as soon as they could be brought to the 

 laboratory. 



The methods of preparation embraced the following variations : 

 Precipitation [after LiHenfeld (19)] of water extracts with 



