332 CENTRAL NERVOUS SYSTEM. 



be demonstrated by the silver-nitrate method, but it is 

 superior to it as regards two points : the reaction can always 

 be obtained with perfect certainty in a certain time ; and 

 the preparations can be perfectly preserved by the usual 

 methods. 



TAL (Gazz. degli Ospitali, 1886, No. 68) finds that if 

 sections made by this process be treated with solution of 

 sodium sulphide, a much darker stain is obtained. Sections 

 may then advantageously be double-stained with Magdala red. 



MAGINI (Boll. Accad. Med. di Roma, 1886 ; Zeit. f. wiss. Mik., 1888, p. 

 87) recommends a development of Golgi's process in which zinc chloride is 

 used in place of sublimate. Portions of tissue of 2 to 3 centimetres .cube 

 are hardened for at least two or three months in Miiller's solution. They 

 are well washed with distilled water, and brought into a 0'5 to 1 per cent, 

 solution of chloride of zinc. This is changed for fresh every day for seven 

 to ten days (until it does not become yellower than bichromate solution). 

 Sections are then made, washed quickly with alcohol, imperfectly cleared 

 (see 677) with kreasote, and mounted in dammar. This process is said to 

 demonstrate better than Golgi's the finer structure of ganglion-cells and 

 their processes. 



Golgi's method may be combined with Weigert's nerve 

 stain (see PAL, Wien. med. Jahrb., 1886; Zeit. f. wiss. Mik., v, 

 1, 1887, p. 93). 



674. Special Stains. For the study of medullated nerve- 

 tracts, we have, first and foremost, WEIGERT'S h&matoxylin 

 process ( 650). 



PAL'S modification of the process ( 651) is said to be very 

 good. 



KULTSCHITZKY (Anat. Anz., 1889, p. 223 ; Zeit. f. wiss. Mik., vi, 2, 1889, 

 p. 196) proposes the following process, as being simpler than Weigert's and 

 giving similar results: Specimens are hardened in solution of Miiller or 

 Erlicki, and imbedded in celloidin. Sections are made and stained for a 

 few hours (up to twenty-four) in a stain made by adding 1 gramme of haema- 

 toxylin dissolved in a little alcohol to a mixture of 20 c.c. of saturated 

 aqueous solution of boric acid and 80 c.c. of distilled water. A little acetic 

 acid (two to three drops to a watch-glass) is added to the stain before using. 

 It is well to treat the sections after staining for twenty-four hours with 

 saturated solution of sodium or lithium carbonate. They should then be 

 washed with alcohol and mounted in balsam. 



A still simpler luumatoxylin stain, which is said to give the same results, 

 is composed of 100 c.c. of 2 per cent, acetic acid, with 1 gramme of hsema- 

 toxylin dissolved in a little alcohol. 



Rossi (Zeit.f. wiss. Mik., vi, 2, 1889, p. 182) also recommends a process 



