CHAPTER XVIII. 



OTHER STAINS AND COMBINATIONS. 



377. Kernschwarz (PLAINER, Zeit. u-iss. Mik., iv, 1887, 

 p. 350). A black liquid on sale by Griibler and H oil born. 

 MAYER (Grundziige 9 LEE & MAYER, 1st ed., p. 202) finds 

 that it contains iron, combined with some gallic acid. I 

 use it as follows : 



Sections (I have not tried material in bulk) are fixed on 

 slides and treated with Kernschwarz until the required depth 

 of stain is obtained, which will be from a few minutes to 

 twenty-four hours, according to the material. 



There is obtained a black or neutral-tint stain, which is 

 either a pure chromatin stain, or at the same time a plasma 

 stain. If overstaining should have occurred, the stain is 

 easily differentiated by means of any weak acid, either in 

 water or alcohol. PLATNER took alkalies, preferably carbonate 

 of lithia, for differentiation. 



It may be well, if a good plasma stain has been obtained, 

 to after-stain for twenty-four hours with safranin, followed 

 by differentiation in either neutral or acid alcohol, and clove 

 oil. The stain is perfectly permanent in balsam, and is 

 stated to be a good one for preparations that it is desired to 

 photograph. 



I greatly recommend this stain, which is safe and easy. 

 The combination with safranin gives a better chromatin 

 stain than safranin alone. 



378. Brazilin, the colouring matter of Brazilian redwood or Pernam- 

 buco wood, has been recommended by EISEN (Zeit. wiss.Mik., xiv, 1897, 

 p. 108), and HICKSON (Nature, Ixii, 1900, p. 589, and Quart. Journ. Mic. 

 Sci., 1901, p. 469). MAYER (Grundziige, p. 203) finds that, in alum 

 solution, it gives a stain similar to that of haematein, but much weaker. 



