416 CHEMISTRY OF THE PROTEIDS CHAP. 



According to Bang, thymus-histone forms with HC1 two kinds of 

 salts, namely, a neutral salt containing 6 Cl, and an acid salt with 

 13 Cl. The 6 valencies of the histone, satisfied by the 6 Cl in the 

 neutral salt, are called the chief valencies, while the additional 7 

 valencies, seen in the acid salt, are called the accessory valencies. 

 Each molecule of histone is linked, normally, to 6 molecules of 

 nucleic acid, each of which has 4 valencies. In each nucleic 

 acid 2 valencies are occupied by alkali-atoms (potassium, calcium), 

 1 valenc}' is firmly linked to the histone - molecule, while the 

 remaining fourth valency in each of the 6 nucleic acids is linked 

 to 6 out of the 7 accessory valencies of histone above referred to. 

 The remaining seventh valency of histone serves to link it to para- 

 histone, which is supposed to possess 4 valencies, one of which is 

 united to the histone, while the remaining three are joined to 3 

 molecules of nucleic acid. 



AUtali} 

 Alkali] 



Nucleic acid < 



Alkali 

 Alkali 



\ f 



f Nucleic acid -> 

 ic oc/</ -| 



( Nucleic 

 Alkali 



/Aa/A 



Nucleic acid 



Alkali} 



Nucleic acid -( ^^~^ ^ 



_; Histone Parahistone 



Alkali} f , ' / / \ 1 (Alkali 



} Nucleic acid \ ' / ' * \-Nucleic J 



Alkali! V' / / V J ac/rf V /Aa// 



Alkali} f 



Alkali/ Nuclei a id 1 / 



[The word alkali means K or Ca. The dotted lines indicate the 7 accessory 

 valencies of the histone and 4 accessory valencies of the para-histone. Bang in his 

 schematic representation, of which the above is a modification, did not represent the 

 accessory valencies of the para-histone, as the neutral para-histone sulphate precipitates 

 albumin much less than does the neutral histone-salt. The Author.] 



As soon as any substance which is a stronger base than histone is 

 brought into contact with histone-alkali-nucleonate, those valencies in 

 the nucleic acid molecules which are satisfied by the 6 accessory 

 valencies of the histone will link up with the stronger base and the 

 histone radical be converted from a 1 3 into a 7 valent base. 



The following analysis of thymus-histone and para-histone have 

 been made : 



[TABLE 



