420 CHAPTER XXXII. 



FISH (Proc. Amer. Mic. Soc., xvii, 1895, p. 319) has also 

 obtained good results with the following mixtures : 



Formalin ...... 2 c.c. 



3 per cent, bichromate . . . 100 



leaving the tissues three days in this liquid and three days in 

 the silver nitrate (f per cent.). 



Or, with advantage : 



Liquid of Miiller . . ^ . 100 c.c., 



10 per cent, formalin . . . 2 



1 per cent, osmic acid . . . 1 



The formalin and bichromate mixtures should be kept in 

 the dark. It is well only to make them up at the instant of 

 using them. 



KOPSCH (Anat. Anz., xi, 1896, p. 727) states that he has 

 obtained good impregnations with a mixture of 4 parts of 

 3*5 per cent, bichromate solution, and one of commercial 

 formaldehyde solution. He considers the results more certain 

 than with the osmic acid mixture. 



G-EEOTA (Intern. Monatsschr. Anat., xiii, 1896, p. 108 ; Zeit. 

 f. wiss. Mik., xiii, 1896, p. 314) first hardens (brain) for a 

 week or two in 5 to 10 per cent, formol solution, then puts 

 small pieces for three to five days into 4 per cent, bichromate, 

 then into the silver. 



SCHEEIBEE (Anat. Anz., xiv, 1898, p. 275) obtained good 

 results (on appendages of Crustacea which were impervious 

 to the osmic mixture) with mixtures of five parts 2*5 per cent, 

 bichromate to one of 4 per cent, formaldehyde, or one part 

 2'5 per cent, bichromate to two of 5 per cent, formaldehyde, 

 the specimens remaining for one day in the first, for two days 

 in the second. 



BOLTON (Lancet, 1898, p. 218; Journ.Roy. Mic. Soc., 1898, 

 p. 244) hardens brain for five weeks or more in formalin, 

 then puts pieces for a few hours to five days into 1 per cent, 

 bichromate of ammonia. 



Similarly BAEI (Zeit. f. wiss. Mik., xvi, 2, 1899, p. 243), 

 using 2 per cent, bichromate of potash. 



VAN G-EHOCHTEN (in litt.) has tried the substitution of 

 formaldehyde for the osmic acid in the G-OLGI process, and 

 has not obtained good results. 



