336 



CEI.L-CIIEMISTR Y AND CELL-PIIYSIOLOG V 



cial iiucleins, prepared by combining egg-albumin witii nucleinic acid 

 in various proportions, show a \arying affinity for basic and acid] 

 dyes according as the nucleinic acid is more or less completely' 

 saturated with albumin. Lilienfeld's starting-point was given by thej 

 results of Kossel's researches on the relations of the nuclein group, 

 which are expressed as follows:^ — 



Nucleo-proteid (i% of P or less), 

 by peptic digestion splits into 



Peptone 



Niicldn (3-4% P). 

 by treatment with acid splits into 



Albuiiii)i 



A'acleiiiiL acid (9-10% P), 

 heated with mineral acids splits into 



Phosphoric acid 



JViich'i)! bases 

 (adenin. guanin. etc.). 



(^A carbohydrate.^ 



Now, according to Kossel and Lilienfeld, the principal nucleo-l 

 proteid in the nucleus of leucocytes is nucleo-Jiiston, containing about! 

 3'y^ of phosphorus, which may be split into a form of nuclein playing 

 the part of an acid, and an albuminoid base, the Jiiston of Kossel ; 

 the nuclein may in turn be split into albumin and nucleinic acid. 

 These four substances — albumin, nucleo-histon, nuclein, nucleinic] 

 acid — thus form a series in which the proportion of phosphorus, 

 which is a measure of the nucleinic acid, successively increases from' 

 zero to 9-10%. If the members of this series be treated with the 

 same mixture of red acid fuchsin and basic methyl-green, the result ! 

 is as follows. Albumin (egg-albumin) is stained red, nucleo-histon 

 greenish blue, nuclein bluish green, nucleinic acid intense green. "Wej 

 see, therefore, that the principle that determines the staining of the 

 nuclear substances is always the nucleinic acid. All the nuclear sub- i 

 stances, from those richest in albumin to those poorest in it, or con- 

 taining none, assume the tone of the nuclear {i.e. basic) stain, but the 

 combined albumin modifies the green more or less toward blue." ^ 

 Lilienfeld explains the fact that chromatin in the cell-nucleus seldom 

 appears pure green on the assumption, supported by many facts, 

 that the proportions of nucleinic acid and albumin vary with different ■■ 

 physiological conditions, and he suggests further that the intense 

 staining-power of the chromosomes during mitosis is probably due j 

 to the fact that they contain a maximum of nucleinic acid. Very 

 interesting is a comparison of the foregoing staining-reactions with 

 those given by a mixture of a red basic dye (saffranin) and a green 

 acid one (" light green"). With this combination an effect is given 

 which reverses that of the Biondi-Ehrlich mixture ; i.e. the nuclein 



1 From Lilienfeld, after Kossel ('92, p. 129). 



- /•'■•, P- 394- 



