250 THE MICROSCOPE AND 



place the whole for two days in a dessicator, with sulphuric acid. 

 (This is best done in a watch-glass or flat-bottomed cell.) The 

 cells are best got on to the slide by pouring a drop of the dehy- 

 drated glycerine on to it. 



Aniline Blue for Processes of Ganglion Cells.— Take sections 

 of cord or brain that have been hardened in bichromate ; wash 

 with acidulated water, stained, in the dark, in a slightly acidulated 

 hydrochloric or acetic acid solution of the soluble aniline blue of 

 commerce. Wash out with acidulated water, rinse quickly with 

 absolute alcohol, clear i7i the dark with creosote, and mount in 

 dammar. N.B. — Do not allow them to remain in the creosote 

 long, and they must be preserved permanently in the dark. 



Carriere's Method* for Ganglion Cells. — Put fresh sections of 

 cord into the three following solutions : — {a) Bichromate of 

 potash, i:6oo; {b) bichromate of potash, 1:500; (r) chromate of 

 ammonia, i :6oo. After ten days remove sections from a and b, 

 wash with water, throw into barely transparent ammoniacal solu- 

 tion of carmine. Five days afterwards the sections from a were 

 easily teased out ; in seven to ten days those from b ; those from 

 c were removed after fourteen days into the carmine solution ; and 

 after three days tease them. By these solutions the anastomoses 

 between cells of anterior cornea may be demonstrated. 



Weigert's Method for Central Nervous System t— Stain the 

 sections, hardened in Miiller's fluid or bichromate of potash, for 

 twenty-four hours in a concentrated watery solution of acid fuchsin 

 (soda-salt of rose-aniline sulphate). Wash in water, and transfer 

 to an alkaline solution of alcohol — viz., 100 cc. of absolute alco- 

 hol with 10 cc. of a solution, made by dissolving i gramme of 

 fused caustic potash in 100 cc. of absolute alcohol, and filtering 

 for a few seconds, until the first sign of the grey nerve tissue of 

 the section becomes visible. Wash in water, which must not be 

 acid, and dehydrate with absolute alcohol saturated with sodic 

 chloride, to preserve the colour of the section. Clear with oil of 

 cloves, and mount in Canada balsam. The blue tint may be 

 increased by putting the sections in a solution of i part of hydro- 



* Arch, fiir Mikr. Anat., xiv. (1877), p. 126. 

 t Centralblatt f. D. Med. Wissenschaflen, 1884, pp. 42—46. 



