236 PRESERVATIVE LIQUIDS. 



As this salt is very hygroscopic, its solution presents the advantage of not 

 drying up, so that it is not necessary to close the mounts until it is desired 

 to put them away. 



376. Chloral Hydrate. 5 per cent, in water (LAVDOWSKY, 

 Arch.f. mik. Anat., 1876, p. 359). 



Or, 2*5 per cent, in water (BRADY, British Copepods). 

 Or, 1 per cent, in water (MuNSON, Journ. Roy. Mic. Soc., 

 1881, p. 847). 



377. Hydrochlorate of Chinolin appears to be a powerful 

 antiseptic (see ROSENTHAL, in Biol. Centralbl., ix, 1890, p. 767; 

 or Zeit.f. wiss. Mik., viii, 3, 1891, p. 342). 



378. Alcohol. Not very recommendable for mounting, as if taken weak 

 it is not a very efficient preservative, and if taken strong it attacks the 

 cement of mounts. 



CABPENTEE (The Microscope') recommends a strength of 1 part to 5 of 

 water. 



The chief use of alcohol for preservation purposes is of 

 course for preserving specimens in till wanted for further 

 preparation and study. See, on this point, the remarks in 

 Chap. I, 2. 



Mercurial Liquids. 



379. Corrosive Sublimate Solution (HABTING'S FLUID, Micro. Diet., 

 art. " Preservation," p. 640). One part of sublimate to from 200 to 500 of 

 water. (For blood-corpuscles of frog 1 400, of birds 1 300, of mammals 

 1 200.) " Harting recommends this as the best preservative for the cor- 

 puscles of the blood, nerve, muscular fibre, &c." 



380. Pacini's Fluids (Journ. de Mic., iv, 1880; Joum. Roy. Mic. Soc. 

 [N.S.], ii, 1882, p. 702). Pacini remarks that "bichloride of mercury coagu- 

 lates and precipitates the albuminous matter that exists in the interstitial 

 fluids of the tissues," and therefore in order to prevent this coagulation it is 

 well to associate with it salt for certain preparations, or acetic acid for others. 

 On this principle are prepared the following classical fluids of Goadby and 

 Pacini : 



FLUID No. 1 is identical with that of Harting given above, viz. 1*200 

 sublimate in water. Pacini uses it for removing, when desired, the salt or 

 acid from preparations that have been placed in one of the other solutions. 

 FLUID No. 2 : 



Bichloride of mercury .... 1 part. 

 Common salt ...... 2 parts. 



Water 200 



Of general employment, but especially useful for blood-corpuscles of cold- 

 blooded animals, as it has a less density than the following fluid. It pre- 



