FIXING AND HARDENING AGMNTS. 49 



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 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 (GILSON, in lilt. 1895). 

 Nitric acid of 46 strength (this 

 would be sp. gr. 1'456, or 80 per 

 cent., nearly) . . . .15 c.c. 



Glacial acetic acid . . 4 



Corrosive sublimate . . .20 grm. 



60 per cent, alcohol . . . 100 c.c. 



Distilled water .... 880 

 When required for marine animals add a few crystals of 

 iodine, which will prevent the formation of precipitates of 

 sea salts. If in any case the preparations should show 

 a granular precipitate, this may be removed by washing with 

 water containing a little tincture of iodine. 



I find that it affords in general a faithful and delicate 

 fixation, and gives to tissues an excellent consistency. 

 Objects may remain in it for a considerable time without 

 hurt. It has a high degree of penetration. A treatment 

 for a few days with it will serve to remove the albumen 

 from the ova of Batrachians. This liquid may he recom- 

 mended to beginners, as it is very easy to work with. For 

 some objects, as I found, the proportion of sublimate may 

 be increased with advantage. 



KOSTANECKI and SIEDLECKI (Arch. mile. Anat., xlviii, 1896, 

 p. 181) take a mixture of saturated sublimate solution and 

 3 per cent, nitric acid in equal parts, or a mixture of equal 

 parts of sublimate solution, 3 per cent, nitric acid, and 

 absolute alcohol, fix for twenty- four hours, and wash out in 

 iodine-alcohol. 



PETRUNKEWITSCH (Zool. Jahrb. Abfh. Morph., xiv_, 1901, p. 

 576) takes water 300, absolute alcohol 200, glacial acetic 

 acid 90, nitric acid 10, and sublimate to saturation. Both 

 this and Gilson's have been much used lately. 



70. Picro-sublimate Mixtures. BABL'S (Zeit iciss. Mik., xi, 

 1894, p. 165). Sublimate, saturated solution in water, 1 



