330 CENTRAL NERVOUS SYSTEM. 



thirty minutes in 2 per cent, chloral solution. SANKEY and 

 STIRLING have also used anilin blue-black, in a much weaker 

 solution, which Bevan Lewis does not recommend. VEJAS, 

 however (Arch f. Psychiatrie, xvi, p. 200), obtained good re- 

 sults by staining from eighteen to twenty-four hours in a solu- 

 tion of 1 in 3000. 



GIERKE (Zeit. f. wiss. Mik., 1884, p. 379) was not able to 

 obtain good results with anilin black procured in Germany, 

 and finds that the treatment with chloral is injurious to the 

 preservation of the tissues. MARTINOTTI (Ibid., p. 478) comes 

 to the same conclusion. 



LUYS (Gaz. Med. de Paris, 1876, p. 346) greatly recommends 

 the anilin colour known as Novr Colin : he stains for three to 

 four minutes in a O'l per cent, solution. 



JELGERSMA (Zeit. f. wiss. Mik., 1886, p. 39) finds that anilin 

 blue-black gives excellent results, provided that the English 

 preparation of the colour be alone employed. He makes solu- 

 tions of MOO, 1-800, and 1'2000, of which the first stains 

 sections in a quarter of an hour, the second in five hours, the 

 third in twelve hours. The stain takes effect on ganglion- 

 cells and their processes, and on axis cylinders, but does not 

 demonstrate neuroglia or connective tissue. 



MARTINOTTI (1. c., 1884, p. 478) finds that picro-nigrosin 

 gives very good results, especially for pathological objects. 

 He stains for two or three hours or days in a saturated 

 solution of nigrosin ( 110) in saturated solution of picric 

 acid in alcohol, and washes out in a mixture of 1 part of 

 formic acid with 2 parts of alcohol until the grey matter 

 appears clearly differentiated from the white to the naked 

 eye. 



Last, but not least, as a general stain we have the sublimate 

 method of GOLGI (Archivio per le Scienze Mediche, 1878, p. 3). 

 This method, which may be said to be in principle identical 

 with the bichromate of potash and silver nitrate method of the 

 author, consists, like the latter, of two processes : 1, hardening 

 in bichromate ; 2, treatment with bichloride of mercury. 



For hardening, use either a solution progressively raised 

 in concentration from 1 per cent, to 2 per cent., or Miiller's 

 solution. Take small pieces of tissue (not more than 1 to 2 

 c.c), large quantities of liquid, and change the latter fre- 

 quently so as to have it always clear. Fifteen to twenty 



