306 RETINA, INNER EAR, NERVES. 



either Miiller's solution, or chromic acid of ^th per cent., or a 

 mixture of one part of wood-vinegar (Acetum pyrolignosum) 

 with three parts of distilled water, which he states gives 

 particularly instructive preparations without any serious altera- 

 tion of the elements. 



CUCCATI (Mem. R. Accad. Sci. 1st. di Bologna ; Zeit. f. wiss. 

 Hik., v, 1, 1888, p. 86) fixes large eyes (the lens and vitreous 

 body having been removed) for two days in a solution of 

 1 per cent, osmic acid .... 14 grammes. 

 1 per cent, chromic acid ... 25 ,, 



Acetic acid 1 drop, 



which should be renewed after the lapse of twenty-four hours. 

 See also DENNISSENKO (Arch. f. mik. Anat., 1881, p. 395). 



645. Staining. May be done in the mass, or sections may 

 be stained. 



The best general stains are alum-carmine (several hours) 

 or (FLEMMING) hasmatoxylin of Delafield or Bohmer (one hour 

 in strong solution, or one day in weak). DOSTOIEWSKY and 

 LIST both recommend double staining with haematoxylm and 

 eosin (see Zeit. f. wiss. Mik., iii, 4, 1886, p. 514). 



BEENHEIMEE'S luematoxylin (see S. B. K., Akad. Wiss. Wien, 1884 ; 

 or Journ. Roy. Mic. Soc., 1886, p. 167). 



RAMON Y CAJAL (Rev. trim, de Hist. Norm, y Path., i, 1888, p. 1 ; Anat. 

 Am., 1889, p. Ill ; Zeit. f. wiss. Mik., v, 3, 1888, p. 373, and vi, 2, 1889, 

 p. 204) applies the silver-nitrate method of Golgi (infra, 652). Fresh 

 retina is hardened for two or three days in a bichromate and osmic acid 

 mixture (for instance, a mixture of four parts 3 per cent, solution of bichro- 

 mate of potash and 1 part of 1 per cent, osmic acid solution), then brought 

 into 0'75 per cent, solution of silver nitrate for twenty-four to thirty hours. 



LENNOX (Arch.f. Ophthalm., xxxii, 1 ; Zeit. f. wiss. Mik., iii, 3, 188(5, 

 p. 408; and Journ. Roy. Mic. Soc., 1887, p. 339) has been applying 

 Weigert's hsematoxylin method to the retina, with some remarkable results. 



CUCCATI (1. c., last ) stained with concentrated aqueous solution of 

 Siiurefuchsin, and mounted in balsam. 



BABEETT (1. c., last ) stains in the mass either with Kleinenberg's 

 luumatoxylin, or with a borax carmine that he attributes to Woodward, but 

 the formula of which much more nearly approaches that of Thiersch. 



KEAUSE (1. c., 647) obtains instructive preparations by treating fresh 

 retina with perchloride of iron or of vanadium in 1 per cent, solution, and 

 then with a 2 per cent, solution of tannic or pJTOgallic acid. These reagents 

 only stain the granule layers, and the nuclei of the ganglion evils. The de- 

 ments of the other layers may then he stained with S-iuvefuclisin. or some 

 other anilin. 



