CHAPTER XV. 175 



method has its raison d'etre for the very special objects for which it 

 was imagined for the researches on cell-granulations for which 

 EHRLICH employed the three colours, or for the researches on the 

 plastin element of cytoplasm for which MARTIN HEIDENHAIN em- 

 ployed the mixture ; for the study of gland cells ; and for similar 

 objects. But to recommend it, as has been done, as a general stain 

 for ordinary work, is nothing but mischievous exaggeration. For 

 it is far from having the qualities that should be possessed by a 

 normal section stain. Workers have at length found this out, and 

 it is now but little used except for the special purposes above 

 indicated. 



296. EHRLICH'S " Triacid " Mixture. This name would seem to 

 indicate that the mixture contains three ' ' acid ' ' colours, which is 

 not the case, methyl green being a strongly " basic " colour. Ehrlich 

 explains in a letter to Mayer (see also EHRLICH and LAZARUS, Die 

 Ancemie, 1898, p. 26) that it is so called " because in it all the three 

 basic groups of the methyl green are combined with the acid dye- 

 stuffs." A very pretty conundrum ! 



The latest receipt (op. cit., p. 28) is as follows : 



Prepare separately saturated solutions of orange G-, Saurefuchsin, 

 and methyl green, and let them clarify by settling. Then mix, in 

 the order given, using the, same measure-glass, 13 to 14 c.c. of the 

 orange, 6 to 7 of the Saurefuchsin, 15 of distilled water, 15 of alcohol, 

 12J of the methyl green, 10 of alcohol, and 10 of glycerin. After 

 adding the methyl green, shake well, but do not filter. 



The mixture keeps well. I find its qualities and defects to be 

 much those of the Ehrlich-Biondi mixture. The stain seems more 

 powerful but less delicate, and the methyl green in it appears to have 

 more resistance to alcohol, so that it is better adapted for ordinary 

 work. 



MAYER (Grundzuge,~LvE, and MAYER, p. 197) has simplified the formula 

 thus : Take 1 g. methyl green, 2 g. orange, 3 g. Saurefuchsin, and 

 dissolve in a mixture of 45 c.c. water, 10 c.c. glycerin, and 20 c.c. alcohol 

 of 90 per cent. 



MOREL and DOLERIS (C. E. Soc. Biol., liv, 1902, p. 1255) mix 1 vol. of 

 the solution with one of 8 per cent, formalin and add 0-1 per cent, of 

 acetic acid, and state that thus the methyl green is better fixed in the 

 nuclei. 



297. PIANESE'S Saurefuchsin-malachite Green (from MULLER, Arch. 

 Zellforsch., viii, 1912, p. 4) consists of 0-5 grm. malachite green, 0-1 grin. 

 Saurefuchsin, and 0-01 grm. Martius yellow in 150 c.c. water and 50 c.c. 

 alcohol. Stain for twenty-four hours, differentiate with alcohol, 

 containing 1 to 2 drops of HC1 per 200 c.c. 



