44 FIXING AND HARDENING AGENTS 



The addition of sodium chloride allows a stronger solution to be 

 obtained than can be made with pure water, and also, it is stated, 

 enhances the penetration of the sublimate. But the fixation-precipi- 

 tates (§ 28) formed by the double salt are (according to Spuler, Encyl. 

 mik. Technik., p. 1274) for the most part soluble in water, thus giving 

 rise to imperfect preservation. 



Concentrated {i.e. over 20 per cent.) solution in sea-water is recom- 

 mended for some marine animals. 



Stoelzner (Zeit. wiss. Mikr., xxiii, 1906, p. 25) recommends 

 saturated solution of sublimate in sugar solution of 4^ per cent., as 

 isotonic (for warm-blooded animals). 



Liquid of Lang {Zool. Anzeiger, 1878, i, p. 14), For Planaria. 



Distilled water 

 Chloride of sodium . 

 Acetic acid 

 Bichloride of mercury 

 (Alum, in some cases 



100 parts. 

 6 to 10 „ 

 6 to 8 

 3 to 12 „ 



part.) 



70. Alcoholic Solutions. Apathy {Mikrotechnik, p. Ill) recom- 

 mends a solution of 3 to 4 grm. of sublimate and 0-5 grm. sodium 

 chloride in 100 c.c. of 50 per cent, alcohol for general purposes. 



Ohlmacher {Journ. Exper. Medicine, ii, 6, 1897, p. 671) takes — 



Absolute alcohol . . . . . ■ 80 parts. 



Chloroform . . . . . . 15 ,, 



Glacial acetic acid . . . . . 5 „ 



Sublimate to saturation (about 20 per cent.). 



" Ordinary pieces " of tissue are sufficiently fixed in fifteen to thirty 

 minutes. Entire human cerebral hemispheres, subdivided by Meynert's 

 section, take eighteen to twenty-four hours. 



For liquids containing a much higher proportion of acetic acid, see 

 Acetic Alcohol. 



71. Acetone Solution. Held {Arch. Anal. Phys., Anat. Abth., 

 1897, p. 227) fixes nerve-tissue in a 1 per cent, solution of sublimate 

 in 40 per cent, acetone, and washes out through increasingly con- 

 centrated grades of acetone. 



72. Phenol Solution. Pappenheim {Arch. Path. Anat., clvii, 1899, 

 p. 23) shakes up carbolic acid with aqueous sublimate solution and 

 filters. 



73. Ciaccio {Arch. Ital. Anat. Embr., vi, 1907, p. 486) has an irrational 

 mixture of sublimate, iodine, and formol. 



74. Mercuro-nitric Mixtures. Frenzel {Arch. iyiik. 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 or 2 c.c. Objects of the size of a pea 

 to be fixed in it for five or ten minutes, then hardened 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. 



