222 EXAMINATION AND PRESERVATION MEDIA 



467. Amann's Lactophenol (from Langeron, C. R. Soc. Biol., 

 Iviii, 1905, p. 750). Carbolic acid, 20 ; lactic acid, 20 ; glycerin, 

 40 ; water, 20. For Nematodes, Acarids, etc. Add gradually 

 drop by drop to the water containing the organisms. Not for 

 mounting. Mount in glycerin jelly. (See also, Amann. Zeit. f. 

 iviss. Mik., 1896.) 



GLYCERIN MEDIA * 



468. Glycerin. Glycerin diluted with water is frequently 

 employed as an examination and mounting medium. Dilution 

 with water is sometimes advisable on account of the increased 

 visibility that it gives to many structures. But for efficacious 

 preservation undiluted glycerin, the strongest that can be pro- 

 cured, should be used (see Beale, How to Work, etc.). 



For closing glycerin mounts, the edges of the cover should 

 first (after having been cleansed as far as possible from super- 

 fluous glycerin) be painted with a layer of glycerin jelly ; as 

 soon as this is set a coat of any of the usual cements may be 

 applied. See next chapter. 



Glycerin dissolves carbonate of lime, and is therefore to be rejected 

 in the pi'eparation of calcareous structures that it is wished to preserve. 



469. Extra-refractive Glycerin. The already high index of refraction 

 of glycerin (Price's glycerin, n = 1-46) may be raised by dissolving 

 suitable substances in it. Thus the refractive index of a solution of 

 chloride of cadmium (CdCl,) in glycerin may be 1-504 ; that of a 

 saturated solution of sulphocarbonate of zinc in glycerin may be 1 -501 ; 

 that of a saturated solution of Schering's chloral hydrate (in crusts) in 

 glycerin is 1-510 ; that of iodate of zinc in glycerin may be brought up 

 to 1-56. For further details see previous editions, or Journ. Roy. Mic. 

 Soc, ii, 1879, p. 346 ; iii, 1880, p. 1051 ; (N.S.), i, 1881, pp. 943 and 366. 



470. Glycerin and Alcohol Mixtures. These afford one of the 

 best means of bringing delicate objects gradually from weak into 

 strong glycerin. The object is mounted in a drop of the liquid, 

 and left for a few hours or days, the mount not being closed. 

 By the evaporation of the alcohol the liquid gradually increases 

 in density, and after some time the mount may be closed, or the 

 object brought into pure glycerin or glycerin jelly. 



1. Calberla's Liquid {Zeit. wiss. Zool., xxx, 1878, p. 442). 

 Glycerin 1 part, alcohol 2, water 3. 



2. We strongly recommend the following for very delicate 

 objects : Glycerin 1 part, alcohol 1, water 2. 



3. Hantsch's Liquid. Glycerin 1 part, alcohol 3, water 2. 



4. Jager's Liquid (Vogt and Yung's Traite d'Anat. Comp. 

 Prat., p. 16). Glycerin 1 part, alcohol 1, sea water 10. 



* Refer to p. 600, § 1188, for directions for bringing objects into 

 glycerin. 



