364 CHAPTER XXVII. 



For some remarks of BATAILLON and KOEHLEE on the stain of borax- 

 methylen-blue see Comptes Eendus, cxvii, 1893, p. 521, or Journ. Roy. 

 Hie. 8oc., 1894, p. 41. 



650. Plasma Stains. I have been unable to discover a 

 single thoroughly satisfactory one. All of those known to me 

 are of an imperfect electivity, in so far as it is difficult if not 

 impossible to limit their action with the desired precision and 

 certitude to the element that it is desired to bring into promi- 

 nence by staining. Almost all of them colour too readily 

 the enchylema or hyaloplasm at the same time as the plas- 

 matic reticulum. And, on the other hand, there are many 

 important elements of cells which cannot be got to stain 

 sufficiently. 



For Kernschwarz see 365. 



Flemming's Orange Method, 283, has been much used. 

 I do not recommend it, as it is very capricious and unreliable. 

 Benda's Safranin and Lightgriin or Saureviolett, 301, gives 

 sometimes splendid results, but is capricious. 



For Saurefuchsin and Orange G- see 287, 288. 



Ehrlich-Biondi mixture is a celebrated plasma stain. It 

 is of no use whatever for polar corpuscles or spindle relics. 

 See 290. 



The Osmic Acid and Pyrog allot Process, 361, gives a 

 very fair and frequently useful plasma stain ; but I do not 

 consider it to be a method of quite the first class. 



The Iron-Haematein Lakes of Benda and M. Heidenhain 

 give good plasma stains, according to the degree of extrac- 

 tion. These are the stains most used for the study of the 

 bodies known as centrosomes, central corpuscles, centrioles, 

 polar corpuscles, etc. See 255. 



It is said by Heidenhain, and by other observers who 

 have repeated his observations, that the stain is obtained in 

 a sharper form by combining the hgematein stain with a fore- 

 going stain with Bordeaux R. He directs (Arch. f. mik. Anat., 

 xlii, 1894, p. 665) that the sections (sublimate sections were 

 used by him) are to be stained for twenty-four hours or more 

 in "a weak " solution of Bordeaux, until they have attained 

 such an intensity of colour as that " they would just be fit 

 for microscopic examination with high powers" (1. c., p. 440, 

 note), and that they be then brought into the ferric alum. 

 After mordanting and staining, the hgematem is to be 



