SECTION SIX 



(c) The quality of the dyes, methyl green and pyronin, is a 

 factor of great importance if good results are to be obtained with 

 this technique. 



(d) In Professor Brachet's original paper (1942) the Unna 

 Pappenheim Methyl Green-pyronin, formula as below, was em- 

 ployed : 



Methyl green, 00 0-15 gm. 



This stain requires very rapid differentiation with the 95% alcohol 

 as the stain, particularly the pyronin is liable to be washed out 

 completely: differentiation here requires a great deal of practice 

 and skill. For this reason Professor Brachet (1953) recommends 

 the modified formula. However, chloroform washed methyl green 

 is somewhat troublesome to prepare, and many workers may 

 prefer to use the original Unna Pappenheim Methyl Green- 

 Pyronin. 



Results: 



Specimen A : 



The presence of ribonucleic acid (of the nucleoli and of the 

 cytoplasm) is indicated as red particles, and the desoxyribonucleic 

 acid (of the chromatin) of the same cell, as blue. 



Specimen B: 



Treatment with hot water abolishes the methyl green staining 

 of desoxyribonucleic (while Feulgen reaction remains unchanged). 

 The absence of the methyl green staining confirms the presence 

 and locali'i^ation of desoxyribonucleic acid. 



Specimen C: 



Ribonuclease brings about a complete loss of basophilia due to 

 ribonucleic acid, not basophilia due to mucopolysaccharides. 

 The absence of the red granules indicates the presence and localiza- 

 tion of ribonucleic acid. The Feulgen reaction of the nuclei is 

 unchanged. 



339 



