104 COCHINEAL AND OTHKB ORGANIC STAINS. 



staining properties of the basic and acid stains, and also the combination of 

 two contrast colours. Israel stains sections in a saturated acetic acid solu- 

 tion, washes in distilled water, and passes rapidly through absolute alcohol 

 to thick cedar-oil, in which the preparations remain definitively mounted. 

 Nuclei blue, protoplasm red. 



195. Kernschwarz (PLATNEK, Zeit.f. wiss. Mik., iv, 3, 1887, 

 p. 350; Journ. Roy. Mic. Soc., 1888, p. 675). Kernschwarz 

 is a black liquid of unknown composition, prepared in Russia. 

 It may be obtained from Griibler (address 93). Sections 

 (sections only, this colour behaving like safranin, for instance) 

 may be stained in a tolerably strong dilution of the concen- 

 trated liquid, and washed out (it may be for some hours) in 

 an alkaline aqueous liquid. Dilute ammonia will do, but it is 

 better to take a not quite saturated solution of carbonate of 

 lithium (you may take a saturated solution, and dilute it with 

 three, four, or more volumes of water). The result is a 

 nuclear stain in the cytological sense; nuclear figures of 

 division are stained deeply, resting chromatin less deeply or 

 not at all, cytoplasm unstained or faintly grey. A peculiarity 

 of this stain, on which much stress was laid by Platner in his 

 first announcement of the colour, is that it stains also the 

 Nebenkern (which of course safranin and the other anilins do 

 not do). 



After some experimentation I feel bound to say that I do not think Kern- 

 schwarz has the importance seemingly claimed for it by Platner. It cer- 

 tainly stains the Nebenkern, but it does so less rather than more effectively 

 than hsematoxylin. Platner seems to have come to this conclusion himself, 

 his latest work on the Nebenkern making no further mention of Kernschwarz, 

 and having been done apparently entirely with hsematoxylin. And as a 

 nuclear stain, Kemschwarz seems to me inferior to htematoxylin, to say 

 nothing of the chromatin-staining anilins. Only in the event of its being 

 found available for staining in the mass (which may be possible, though I 

 have not succeeded in it) will Kernschwarz, as it seems to me, be found to be 

 an important reagent. 



196. Other Stains. Litmus, red cabbage, bilberry juice (" myrtillus "), 

 black currant juice ("ribesine "), and walnut juice (" nucina"), have been 

 recommended by Lawson Tait, Lavdowsky, Fol, and Leon respectively. 

 They do not appear to call for further notice here. 



