386 CHAPTER XXX. 



Neuroglia, 1895, quoted from Neuyol. Centralb., 1895, p. 

 1146) puts portions of material of not more than half a 

 centimetre in thickness for four days into a " 4 per cent, 

 solution of formol " (by which is presumably meant com- 

 mercial formol diluted with 9 volumes of water). 



MARCUS (quoted from FISH, see below ; see also Zeit. f. 

 wiss. Mik.j xiii, 1896, p. 241) recommends hardening the 

 spinal cord for two or four weeks in a ^ per cent, solution 

 of formalin, then small pieces one half-centimetre thick are 

 cut out and placed in Mulleins fluid for a week in an oven 

 at 37 C. 



VAN GIUSON (An at. Anz., x, 1895, p. 494) states that he 

 obtained good results by using " solutions of formalin of 4, 

 6, and 10 per cent.," followed by 95 per cent, alcohol. 

 Myelin was found to be well preserved and to give the 

 characteristic blue reaction with Weigert's hsematoxylin (the 

 1885 method), just as if a chrome salt were present. 



LACHI (cf. Zeit. f. wiss. Mik., xii, 1895, p. 32) states that 

 he has had good results with <( 20 per cent, solutions of 

 formol." 



FISH (Proc. Amer. Mic. Soc., xvii, 1895, p. 319) recom- 

 mends 



Water , . 2000 c.c. 



Commercial formalin . . . 50 



Sodium chloride . . . .100 grms. 



Zinc chloride . . . . 15 



Brains should be left in this mixture for a week or ten days 

 or more, then transferred to a 2'5 per cent, solution of 

 formalin (water 2000 c.c., formalin 50 c.c.), in which they 

 may remain indefinitely if the jar be kept tightly covered. 



PARKEK and FLOYD (Anat. Anzeiger, Bd. xi, 1895, No. 5, 

 p. 156) find that a f4 2 per cent, solution of formol," by 

 which is meant a mixture of two volumes of formol with 9 

 of water, will harden a sheep's brain in a week or ten days 

 in a satisfactory manner as regards consistency, but with a 

 marked increase of volume, which may amount to as much 

 as 40 per cent. ! To obviate this they advise a mixture of 

 Alcohol 95 per cent. . . .6 volumes, 



Formol 2 per cent, (the above mixture) 4 

 which has the same excellent and rapid hardening qualities 

 and gives only a .J^ardly perceptible increase of volume. 



