EXAMINATION AND PRESERVATION MEDIA. 2^3 



436. Squire's Glycerin Jelly (Squire's Methods and 

 Furmulse, etc., p. 84). — Soak 100 gi-ms. of French gelatin in 

 chloroform water, drain when soft, and dissolve with heat in 

 750 grms. of glycerin. Add 400 grms. of chloroform water 

 with which has been incorporated about 50 grms. of fresh 

 egg-albumen ; mix thoroughly, and heat to boiling-point for 

 about five minutes. Make up the total weight to 1550 grrns. 

 with chloroform water. Filter in a wai'm chamber. 



437. Heidenhain {Zeit. wiss. Mik., xx, 1905, p. 328) takes 

 of gelatin 9 parts, glycerin 7, and water 42, and to the 

 filtrate adds drop by drop 14 parts of absolute alcohol. 



438. Fischer {ibid., xxix, 1912, p. 65) takes 5 grms. of 

 borax disolved in 240 c.c. of water and adds 25 c.c. of 

 glycerine. To this he adds 40 grms. of gelatin, dissolves 

 with heat, and continues to heat gently until the solution has 

 somewhat thickened. This remains fluid at ordinary 

 temperatures. 



439. Gilson's Chloral Hydrate Jelly (communicated by 

 Gilson). — 1 vol. of gelatin, melted secimdum arlem, and 

 1 vol. of Price's glycerin. Mix, and add crystals of chloral 

 hydrate until the volume has increased by one half ; warm 

 till dissolved. This gives a very highly refractive medium. 



Geoffeoy, Journ. de Botan., 1893, p. 55 (see Zeit wiss. Mik., 

 ix, 1893, p. 476) dissolves, by the aid of as little heat as 

 possible, 3 to 4 grms. of gelatin in 100 c.c. of 10 per cent, 

 aqueous solution of chloral hydrate. 



High Refractive Liquids. 



440, Stephenson's Binio&ide of Mercury and Iodide of Potas- 

 sium {Journ. Roy. Mic. Soc. [N. S.J, ii, 1882, p. 167).— A 

 solution prepared by adding the two salts to water until 

 each is in excess; the liquid will then be found to have a 

 refractive index of 1'68. (If [Amann, Zeit. wiss. Mik., xiii, 

 1896, p. 21] glycerin be taken instead of water, it rises to 

 1-78 or 1"80. Behuens [Tabellen, 1898, p. 71] takes binio- 

 dide 65 parts, iodide 50, and water 25, n = 1*71.) Any 



