CHAPTER XVIII. 



OTHER STAINS AND COMBINATIONS. 



377. Kernschwarz (PLATNER, Zeit. wiss. Mik., iv, 1887, p. 350). 

 A black liquid on sale by Griibler & Hollborn. MAYER (Grundzuge, 

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

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

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



Iron- Brazilin (HICKSON, Quart. Journ. Micr. Sci., xliv, 1901, 

 p. 470) is better. Sections are mordanted for one to three hours in 

 1 per cent. sol. of iron alum in alcohol of 70 per cent, (made by 

 dissolving 1 grm. of the salt in 23 c.c. of water, warm, and adding 

 77 c.c. of 90 per cent, alcohol after cooling), rinsed with alcohol, and 

 put for three to sixteen hours into 0-5 per cent. sol. of Brazilin in 

 alcohol of 70 per cent. 



379. Orehella (Orseille), see WEDL (Arch. path. Anat., Ixxiv, p. 143) 

 and FOL (Lehrb., p. 192), and early editions of this work. 



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