482 NEUROGLIA AND SENSE ORGANS. 



formalin, then for four to eight in saturated solution of picric acid (or 

 for the same time in a mixture of the two), then mordants for four to 

 six days at 37 C. in 5 per cent, solution of ammonium bichromate, 

 makes sections (celloidin) and stains them in Weigert's fibrin stain. 



STORCH (Virchow's Archiv., clvii, 1899, p. 127), instead of mordanting 

 the material in bulk with the copper fluid, first makes celloidin sections 

 and then mordants them. 



BARTEL (Ztschr. wiss. Mikr., xxi, 1904, p. 18) first makes paraffin 

 sections and treats them with all the reagents used by Weigert without 

 removing the paraffin, until they have passed the aniline -xylol mixture 

 which should consist of 1 part of aniline to 10 of xylol (or more), and be 

 allowed to act for twelve to twenty -four hours. 



SAND uses material fixed as for his neurofibril stain ( 843), and 

 stains it according to Weigert. 



See also AGUERRE, Arch. mik. Anat., Ivi, 1900, p. 509 ; KRAUSE, Abh. 

 k. Akad. Wissench. Berlin. Anhang, 1899; WIMMER , Centrbl. allg, 

 PatJiol u. pathol. Anat., xvii, 1906, p. 566 ; GALESESCU, C. E. Soc. 

 Biol, Ixv, 1908, p. 429. 



RUBASCHKIN (Arch. mik. Anat., Ixiv, 1904, p. 577) recommends 

 injecting centres of small mammals with the fixing liquid. To make 

 this, take 100 parts of 2 -5 per cent, solution of potassium bichromate 

 and -5 to 1 of copper acetate, boil, and add 2 -5 to 5 of glacial acetic 

 acid. To this (which may be kept in stock) add, just before use, 10 

 per cent, of formol. Inject warm, and after ten minutes dissect out 

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

 Dry superficially, put for six to twelve hours in 95 per cent, alcohol 

 and embed 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 aniline or clove oil, and pass through 

 xylol into balsam. The method gives very sharp results with 

 small mammals. 



912. BENDA'S Method (N enrol. Centrbl, xix, 1900, p. 796 ; and 

 his article ' Neurogliafarbung," 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 in officinal nitric acid 1 part, 

 and distilled water 10 parts ; for another twenty-four hours in 

 2 per cent, potassium 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-four hours), then in benzol (twenty-four hours), and lastly 

 embedded slowly in paraffin, this being dissolved in benzol to 

 saturation first at room temperature, then successively at 38, 42 



