ix THE NUCLEO-HISTONES 413 



is insoluble in water, and as its compounds with earthly alkalies are 

 slightly soluble, it must be present in the watery thymus extract 

 probably as an alkali-salt, and therefore the following interaction must 

 take place on adding calcium chloride to a watery extract of the 

 thymus : 



Soluble sodium - nucleo-histonate + CaCl 2 

 = Insoluble calcium - nucleo-histonate + NaCl. 



The dissolving action of ions with stronger electro -affinities is 

 exceedingly interesting, and has been fully discussed by the author, as 

 far as corrosive sublimate and sodium chloride are concerned, in his 

 Physiological Histology. See this book, pp. 308-313. 



The solubilities of the salts of nucleo-histone are, according to 

 Huiskamp, as follows : 



Alkali salts : soluble in water ; more or less insoluble in very 

 dilute alkali salt solutions, 0*9 per cent NaCl; soluble in excess 

 of salts. The sodium nucleo-histone is a viscous precipitate 

 readily soluble in water without the addition of ammonia. 



Magnesium salt: fairly soluble in water; insoluble in 0*1 0'3 per 

 cent MgS0 4 ; soluble in excess of salt. 



Calcium salt: slightly soluble in water ; insoluble in Q'l-0'5 per 

 cent CaCl 2 ; soluble in 2 per cent CaCl 2 . 



Barium salt: slightly soluble in water ; insoluble in 0' 11*8 per 

 cent BaCl 2 ; soluble in excess. 



Heavy metals : insoluble in water and insoluble in salt solutions. 



Ammonium sulphate, potassium and sodium nitrate, potassium 

 oxalate and tartrate, first precipitate and in excess dissolve the 

 precipitate. 



To obtain the nucleo-proteid from the watery extract of the 

 thymus, Huiskamp first removes the nucleo-histone with calcium 

 chloride, as described above, and then adds acetic acid to the filtrate. 



Bang 1 minces perfectly fresh thymus-glands (500-1000 grammes), 

 and extracts for 24-48 hours with 0'9 per cent NaCl (1J 2 litres), a 

 few drops of chloroform are added if necessary. The extract so ob- 

 tained, after having been centrifugal ised and filtered, is milky in 

 appearance, and % distinctly amphoteric in reaction, although more basic 

 than acid ; the gland apparently had undergone no change. 



Bang obtains, apart from globulin, from the thymus a nucleo- 

 proteid, a nucleo-histone, and Fleroff 's paratone ; the nucleo-proteid is 

 prepared from the extract by first precipitating the nucleo-histone by 

 the addition of CaCl 2 to the extent of 0'2 to 0*3 per cent, and then 



1 Ivar Bang, Hofmeisters Beitrage, 4. 115 (1903). 



