522 MYELIN STAINS 



iron alum and then in a solution of borax 10 grm., potassium 

 ferricyanide 12-5 grm., distilled water 1000 c.c, the sections are 

 washed three times in tap-water, a few drops of ammonia being 

 added to the second washing water. If sections are over 30 n in 

 thickness, Weil mordants first in 5 per cent, potassium bichromate, 

 washes twice in tap-water before staining, and after differentiation 

 treats them with J per cent, potassium permanganate and then, 

 following a quick wash in tap-water, with a solution of oxalic 

 acid 2-5 grm., sodium bisulphite 2-5 grm., distilled water 1000 c.c. 



Olivecrona {Centrbl f. Allg. Path. a. Path. Anat., xxviii, 

 1917, p. 521) places frozen sections cut at 15 to 20 ju, in 20 per 

 cent, alcohol and then transfers them to 70 per cent, alcohol for 

 ten minutes before staining for one hour in a freshly prepared 

 mixture of 2 parts of a 1 per cent, solution of hgematoxylin in 

 95 per cent, alcohol and 1 part of a solution containing liquor 

 ferri perchloride 4 c.c, concentrated hydrochloric acid 1 c.c, 

 distilled water 100 c.c The sections are differentiated, after 

 washing in tap water, in liquor ferri perchloride 8 c.c, con- 

 centrated hydrochloric acid 1 c.c, distilled water 100 c.c After 

 washing in distilled water the sections are placed for fifteen 

 minutes in water to which a few cubic centimetres of a concentrated 

 aqueous solution of lithium carbonate have been added. 



Loyez' and Weil's methods are now widely used in pathological 

 anatomy. If a colourless background is desired, stain for one to 

 two hours at 45° to 50° C, and differentiate by acid alcohol, or 

 by Pal's oxalic acid-sodium sulphite mixture {vide § 1058). 



Benda's Rapid Method {Berlin kUn. Wochenschr., xl, 1903, p. 748). 

 Sections of formol material by the freezing process (alcohol being 

 avoided) are stained (without any mordanting) for twenty-four hours in 

 Boehmer's hsematoxyhn, differentiated with Weigerfs ferricyanide, and 

 mounted in balsam. Only recommended for peripheral nerves, or for 

 preliminary examination of the central nervous system. 



Nageotte (C. R. Soc. Biol., Ixv, 1908, p. 408) recommends fixing in 

 10 per cent, formalin to which is added from 1 to 7 per cent, sodium 

 sulphate. The sections are cut by the freezing method, and stained 

 for half an hour at 45° to 50° C. in Mayer's haemalum, washed and 

 differentiated in borax-ferricyanide. 



Similarly the Enzycl. mik. Technik., 1910, ii, p. 239, with fresh 

 material cut by the freezing process, and the sections mounted in 

 laevulose (as alcohol somewhat extracts the stain). 



1055. Weigert's Methods. There have been in all three 

 methods of Weigert : the 1884 method, the 1885 method, and 

 the 1891 method. 



The 1884 method {Fortschr. d. Med., ii, 1884, pp. 120, 190 ; 

 Ztschr. wiss. Mikr., i, 1884, pp. 290, 564), which depends on the 

 formation of a chrome lake of haematoxylin, may be considered 

 as superseded. Not so the two others, which depend on the 

 formation of a copper lake in addition to the chrome lake. 



