CYTOCHEMICAL TECHNIQUES FOR NUCLEIC ACIDS 75 



TABLE II 

 The Effect of Various Treatments on Feulgen Intensity" 



° Values in arbitrary units represent means of 10 measurements on tetraploid nuclei of formalin-fixed 

 mouse liver. The Feulgen reagent, unless otherwise specified, contained 0.5% basic fuchsin (National An- 

 iline, dye content 97%), 1% NazSjOs , and had a pH of 2.1. 



case one tissue of known DNA content was used for reference. More exten- 

 sive comparisons of this type are badly needed. 



Certainly the most striking indication of the quantitative nature of the 

 Feulgen reaction can be seen by an analysis of the data obtained when 

 nuclei are measured. As indicated by Ris and Mirsky^" and many others 

 since then, the means of values for the polyploid classes in rat or mouse 

 liver fall into a 1:2:4:8 series. With accurate measuring of normal adult 

 liver, there is no overlap at all between classes, and the means match the 

 theoretical geometrical progression by less than 5%. When hver is com- 



