CHAPTER XXXV. 495 



20 per cent., and ending with absolute, taking five days from first 

 to last. 



Similarly ROCHON-DUVIGNEAUD (Arch. Anat. Micr., ix, 1907, p. 317). 



Other hardening liquids, however, also give good results, provided 

 that the fixation by the osmic acid has been properly performed : 

 amongst them liquid of Flemming, and that of Miiller. Formalde- 

 hyde mixtures he does not recommend. 



LEBER (Munch, med. Wochenschr., xli, 1894, p. 605 ; Zeit. wiss. Mik., 

 xii, 1895, p. 256) advises a solution of formol 1, water 10. After a few 

 days hardening in this, the eyes may be cut through, it is said, without 

 derangement of the parts. The retina lies flat, and is at least as well 

 preserved as with solution of Miiller. 



See also HIPPEL (Arch. f. Ophthalm., xlv, 1898, p. 286 ; Zeit. wiss. 

 Mik., xvi, 1899, p. 79), who finds that formol fixes the lens badly, the 

 retina well, so far at least as the absence of folds from shrinkage is con- 

 cerned ; and HERZOG (Arch. mik. Anat., Ix, 1902, p. 517, and Encycl. 

 mik. Technik., p. 75), who also approves of formol, but insists that it 

 should be acid, and adds 3 to 5 per cent, of acetic acid. 



KOLMER (Arch. Gesammte Phys., cxxix, 1909, p. 35), fixes for twelve 

 to twenty -four hours in a mixture of 4 parts saturated solution of bichro- 

 mate, 4 of formol of 10 per cent., and 1 of acetic acid. 



BENDA (Verh. Ges. Naturf. Mrzte, Ixxi, Vers., 1900, p. 459) fixes in 

 nitric acid of 10 per cent., and hardens in liquid of Miiller, twenty-four 

 hours in each. 



ZtiRN (Arch. Anat. Phys., Anat. Abth., 1902, Supp., p. 106) advises 

 (for mammals) fixing in saturated solution of sublimate in salt solution of 

 0-6 per cent., with 1 to 1| per cent, of acetic acid after removing the 

 anterior pole and the vitreous. Wash out in alcohol of 35 per cent, 

 made 5 per cent, stronger each day up to 50 per cent. ; then pass on to 

 stronger and cedar oil and paraffin. 



923. Staining. For general views I recommend iron-hsematoxylin, 

 followed by Saurefuchsin or Picro-Saurefuchsin, or preceded by 

 Bordeaux ; or Kernschwarz, followed by safranin, or the Ehrlich- 

 Biondi stain. 



The Methylen-blue intm-vitam stain has given valuable results ; 

 see the methods of DOGIEL. 



But the most important method is the bichromate and silver 

 impregnation of GOLGI, first applied to this object by TARTUFERI 

 (Intern. Monatsschr., iv, 1887, p. 421). This author employed the 

 rapid process. So also RAMON Y CAJAL (La Cellule, ix, 1893, p. 121) 

 with the double-impregnation process, 886. To avoid the forma- 

 tion of precipitates on the tissues, he covers the retina, before 

 silvering, with a piece of peritoneal membrane, or a thin layer of 

 collodion. Or, better, he rolls the retina (op. >., p. 130). After 



