NRRVOUS SYSTHM — OYTOLOfirCAr, MUTHODS. 389 



neutral red, dehydrates in alcoholj and passes through 

 bergamot oil to balsam. 



Rosw {Deutsche med. Wuchenschr., 1898, No. 39, p. 615; 

 Zeit. wiss. Mik., xvi, 1899, p. 238) stains in concentrated 

 aqueous solution, washes out thoroughly with water, and 

 passes through alcohol (must be free from acid) into xylol 

 and balsam. Granules of Nissl red, nucleoli red, all the 

 rest yellow. 



763. Alizarin.— See § 751. 



764. Cresyl Violet. — Bielschowsky & Puen {Neurol. 

 Centralb., 1900, p. 1141) stain for 24 hours in 50 c.c. of 

 water, with 6 to 10 drops of concentrated aqueous solution 

 of Oresyl violet RR. and pass through water, alcohol, cajoput 

 oil and xylol into balsam. The preparations keep better than 

 thionin or toluidin blue ones. 



765. Tigroid Substance, other Methods. — See Oox, Zeit. tviss. 

 Mih., xiii, 1896, p. 498 ; xv, p. 369 ; xvi, 1899, p. 101 ; Anat. Hefte, xxxi, 



1898, p. 75 ; Intern. JMonaisscTir., xv, 1898, H. 8 ; Avbub Aca, Monatssshr. 

 Psychiatiie, iv, 1898, p. 31 ; Zeit. wiss. Mik., xv, 1899, p. 493 ; Buehler, 

 Verh. Phys-Med. Ges. Wilrzburg, xxxi, 1898, p. 285 ; Zeit. wiss. Mik., xv, 



1899, p. 351; MossE, Arch. mikr. Anat., 1902, p. 403 (bis ai-gentamin 

 stain, which see). 



B. Methods for Cells and Fibres, demonstrating Neurofibrils. 



766. Neurofibrils; General Characters. — Nerve-cells, and the 

 fibres into which they are prolonged, contain, in addition to 

 the chromatic, basophilous element demonstrated by the 

 method of Nissl, a characteristic " achromatic " element, 

 consisting chiefly of fine, fairly refractive fibrils, which can 

 only be seen with difficulty in the unstained state, and can 

 only be well brought out by means of special stains. They 

 may be fixed with osmic acid, and made out in thin sections 

 of medullated nerves studied in dilute glycerin or water, 

 and may be, to a certain extent, isolated by maceration. 



KuPFPBE (Sitzh. math. Kl. Alcad. wiss. Miinchen, xiii, 1884, p. 470) 

 proceeded as follows : A medullated nerve is stretched on a cork and 

 treated for twenty-four liours with 0'5 per cent, osmic acid. It is then 

 washed in water for two hours and stained for twenty four to twenty- 

 eight hours in saturated aqueous solution of Siiurefuchsin ; after which 



