FIXING AND HARDENING AGENTS. 57 



67. Corrosive Sublimate (LANG'S formula, Zool. Anzeiger, 1878, i, 

 p. 14). For Planaria. Take- 

 Distilled water . . . 100 parts by weight. 

 Chloride of sodium . . 6 to 10 parts. 



Acetic acid . . . . 6 to 8 

 Bichloride of mercury . . 3 to 12 ,, 

 (Alum, in some cases . . .) 



Second formula (ibid., 1879, ii, p. 46). Make a concentrated solution of 

 corrosive sublimate in picro-sulphuric acid, to which has been added o per 

 cent, of acetic acid. 



68. Other Simple Aqueous Solutions. A solution containing 5 g. 

 sublimate, 0'5 g. sodium chloride, and 100 c.c. water, has been quoted as 

 " solution of GATTLE." 



KAISEB'S solution consists of 10 g. sublimate, 3 g. glacial acetic acid, 

 and 300 g. distilled water (from Zeit.f. wiss. Mik., xi, 3, p. 378). 



M. HEIDENHAIX has recommended a O'o per cent, solution of sodium 

 chloride saturated while hot with sublimate. 



69. Alcoholic Solutions. APATHY (Mikrokrltnik, p. Ill) 

 writes that he thinks that " a solution of 3 to 4 grammes of 

 sublimate and 0'5 gramme sodium chloride in 50 per cent, 

 alcohol" (quantity not stated!) will prove to be "for most 

 objects the best of fixatives for general purposes." 



For CAUNOY'S and OHLMACHEK'S alcoholic fluids, si-c- 84. 



69a. HELD (Arcli. f. Anal. u. Phy*., Abth. 1897, p. 227, 

 fixes nerve tissue in a 1 per cent, solution of sublimate in 4 

 per cent. Aceton, and washes out through increasingly-con- 

 centrated grades of aceton. 



70. Mercuro-nitric Mixtures. FKENZKL (Arch.f.mik.Anat., 

 xxvi, 1885,, p. 232) recommends a half-saturated solution 

 of sublimate in 80 per cent, alcohol, to which is added nitric- 

 acid in the proportion of 1 drop to 1 c.c. or 2 c.c. Objects 

 of the size of a pea to be fixed in it for five or ten minutes, 

 then hardened (? how long) in the same sublimate alcohol 

 without the acid, and finally in 90 per cent, alcohol. It is 

 said that the nitric acid renders after-treatment with iodine 

 unnecessary. 



GILSON'S Mixture. I am indebted to Prof. GILSON for 

 kindly sending his latest formula (1895), which is as follows 

 (I have simplified it by omitting- one place of decimals) : 



