448 CHAPTER XXXIII. 



a few seconds drops them face downwards into a solution 

 of- 



Absolute alcohol saturated with eosin . 25 c.c. 

 Pure ether . . . . 25 ,, 



Sublimate in absolute alcohol (2 grms. 



to 10 c.c.) ..... 5 drops. 



After three or four minutes they are washed, stained for 

 one minute in saturated aqueous solution of methylen blue, 

 or in haemalum, washed, dehydrated, and passed through 

 xylol into balsam. Staining with Ehrlich/s triacid also 

 gives good results. 



JENNER (Lancet, 1899, No. 6, p. 370; Journ. Ii'ny. Mic. 

 Soc., 1899, p. 231) mixes equal parts of 1"2 to 1'25 per cent, 

 water-soluble eosin (Griibler) and 1 per cent, methylen blue, 

 filters after twenty-four hours, washes the precipitate on the 

 filter, dries it, dissolves it in 200 parts of pure methyl 

 alcohol, and puts cover-glass preparations into the solution, 

 in which they are fixed and stained in three minutes. (The 

 above mentioned precipitate is a " neutral ' colour, see 

 p. 194.) 



Or, simply mix 125 c.c. of 0'5 per cent, solution of the 

 eosin in methyl alcohol with 100 c.c. of 0'5 per cent, solution 

 of methylen blue. 



WERMEL (Zeit. f. wiss. Mik., xvi, 1899, p. 50; Journ. Roy. Mic. Soc. r 



1899, p. 452) gives some extremely complicated methods of fixing and stain- 

 ing in solutions of methylen blue, eosin, etc., in formol, which I am not sure 

 that I rightly understand. 



See, for the action of formaldehyde on red corpuscles, and for some formol 

 mixtures, MAECANO, Arch. d. Med. Exper., xi, 1899, p. 434 ; Zeit.f. wiss. 

 Milt., xvi, 3, 1899, p. 364; also a method of KIZEB, Journ. Roy. Mic. Soc., 



1900, p. 128. 



Most recent authors are agreed that by far the most faith- 

 ful fixing agent for blood-corpuscles is osmic acid. A drop 

 or two of blood (BioNDi recommends two drops exactly) is 

 mixed with 5 c.c. of osmic acid solution, and allowed to 

 remain in it for from one to twenty-four hours. The exact 

 degree of concentration of the osmic acid solution is a 

 somewhat important point, and must be made out by experi- 

 ment for each form. As a rule it should be strong, 1 to 2 

 PIT cent. According to BIONDI, 2 per cent, is best. Fixed 

 specimens may be preserved for use in acetate of potash 



