540 NEUROGLIA AND SENSE ORGANS 



harden in the same fluid for five to seven days at 35° to 40° C. Dry 

 superficially, put for six to twelve hours into 95 per cent, alcohol and 

 imbed in celloidin or paraffin. Stain sections on the slide for six to 

 twelve hours in saturated aqueous solution of methyl violet B ; treat 

 for half a minute to a minute with Gram's iodine in iodide of potassium ; 

 differentiate in anilin or clove oil, and pass through xylol into balsam. 

 The method gives very sharp results with small mammals. 



1085. Benda's Method {Neurol. Centrbl, xix, 1900, p. 796 ; and his 

 article " Neurogliafdrbung,''' Enzykl. mik. Technik, ii, 1910, p. 308) is 

 as follows : — The material is to be fixed in 90 or 93 per cent, alcohol for 

 no less than two days. Pieces, not thicker than J cm. are put for 

 twenty-four hours into officinal nitric acid 1 part, and distilled water 

 10 parts ; for another twenty-four hours in 2 per cent, potassimn 

 bichromate ; for forty-eight hours in 1 per cent, chromic acid. After 

 washing for twenty-four hours, they are dehydrated in alcohols of 

 ascending strength, cleared first in creosote (twenty-fours), then in 

 benzol (twenty-four hours), and lastly imbedded slowly in paraffin, 

 this being dissolved in benzol to saturation first at room temperature, 

 then successively at 38°, 42° and 45° C, so that pure paraffin, melting 

 at 58° C, is used only for the imbedding proper. 



The sections, stuck to slides, are mordanted for twenty-four hours in 

 4 per cent, iron almn or in 50 per cent. Liquor ferri sulfurici oxydati 

 P.G. thoroughly washed, put for two hours into an amber-yellow 

 aqueous solution of sodium sulfalizarinate as directed in § 697, rinsed 

 with tap-water, and put to stain in 01 per cent, toluidine blue either 

 for fifteen minutes by warming until vapour arises, or for twenty-four 

 hours at room temperature. After rinsing in 1 per cent, acetic acid or 

 in a very dilute solution of picric acid, the sections are dried with filter 

 paper, passed through absolute alcohol, and differentiated for about ten 

 minutes with creosote. They are then dried once more with filter paper, 

 washed with xylol and mounted in balsam. 



Besides this, Benda recommends hardening and making paraffin 

 sections as above, then staining by Weigert's method (§ 1083), but with- 

 out passing the sections through the saturated solution of " chromogen," 

 and using instead of Weigert's methyl violet solution a freshly-prepared 

 mixture of 1 volume of saturated solution of crystal violet, 1 volume of 

 1 per cent, acid alcohol, and 2 volvmies of anilin water. 



Benda also uses Heidenhain's iron haematoxylin to stain paraffin 

 sections of pieces treated as described, differentiating either with 2 per 

 cent, iron alum or with Weigert's borax-ferricyanide mixture. 



1086. Mallory's Haematoxylin Stains (Journ. Exper. Med., 

 V, 1900, p. 19). Zenker fixed tissues are cut in paraffin and after 

 treatment with iodine and hyposulphite are put for a quarter of 

 an hour into 0-5 per cent, solution of potassium permanganate, 

 washed and put for another quarter of an hour into 1 per cent, 

 solution of oxalic acid, well washed and stained for twelve to 

 twenty-four hours or more in Mallory's phosphotungstic hcema- 

 toxylin. Wash, dehydrate in 95 per cent, alcohol, clear with 

 origanum oil, mount in xylol-balsam. Axis-cylinders and nerve- 

 cells pink, neuroglia fibres and myelin blue. To get a more 

 isolated stain of neuroglia, the sections should be brought for 

 five to twenty minutes, after staining, into a 30 per cent, alcoholic 

 solution of iron sequichloride. Neuroglia, fibrin and nuclei blue, 

 the rest colourless. 



