EXAMINATION AND PRESERVATION MEDIA 221 



456. Tannin (Caunoy, Biol. CcHnhiirc, p. 95). Water 100 grm., 

 powdered tannin ()-10 grni., as an examination niedinni only. 



457. WiCKEHSHEiMEu's Fluid (Zool. .Inz., 1879, p. G70). Worthless 

 for histological purposes. 



458. Medium of Farrants (Beale, Hoxv to ]Vork\ etc.. p. 58). 

 Picked gum arabic 4 oz., water 4, glycerin 2. See also the Micro- 

 graphic Dictionary, and A. F. Stanley Kent, in Jourii. Roij. 

 Mic. Soc, 1890, p. 820. 



459. Gum and Glycerin Medium (Langerhans, Zool. Anzeig., ii, 1879, 

 p. 575). 



Gummi arab. ...... 50 



Aquae ....... 50 



to which after twelve hours are added — 



Glycerini . . . . . . .5-0 



Sol. aquosa acid, corbal. (5100) . . . 100 



460. Allen's Gum and Glycerin. Prof. F. J. Allen (in litt.). 

 Solution of gum arabic of the consistency of glycerin, strained, 

 and |- volume of glycerin and /o of formol gradually incorporated. 

 Sets hard. 



461. Hover's Gum with Chloral Hydrate or Acetate of Potash {Biol. 

 Centralb., ii, 1882, pp. 'l',i, 24). A high 60 e.c. glass with a wide neck 

 is filled two-thirds full with gum arabic (in pieces), and then cither a 

 solution of chloral (of several per cent.) containing 5 — 10 per cent, of 

 glycerin is added or oflicinal solution of acetate of potash or ammonia. 

 Filter after solution. The solution with chloral is for carmine or 

 hjematoxylin objects — that with acetate for anilin objects. 



462. Cole's Gum and Syrup Medium. See last ed. 



463. Apathy's Gum and Syrup Medium (see § 511). This 

 medium sets very hard and may also be used for ringing glycerin 

 mounts. 



464. F'abre-Domergue's Glucose Medium {La Nature, No. 823, 

 9 Mars, 1889, supp.). Glucose syrup diluted to 25° of the {erometer 

 (sp. gr. 11968) 1,000 parts, methyl alcohol 200, glycerin 100, camphor 

 to saturation. The glucose is to be dissolved in warm water, and the 

 other ingredients added. The mixture, which is always acid, must be 

 neutralised by the addition of a little potash or soda. It is said to 

 preserve without change almost all animal pigments, but the mounts 

 do not keep indefinitely. 



465. Brun's Glucose Medium (from Fai?re-1)omkr«ue's Premiers 

 Principes dii Microscope, 1889, p. 12;j). Distilled water 140 parts, 

 camphorated spirit 10, glucose 40, glycerin 10. Mix the water, glucose, 

 and glycerin, then add the sj)irit, and filter. Henneouv informed Lee 

 that this liquid preserx ed the colour of preparations stained with anilin 

 dyes, met h 1/1 green included. 



466. Levulose is recommended by Hkmkens, Koshei, u. 

 ScniEEFEunECKKR {Dds Miliroshop, etc., 1889). It is uncrystallisable, 

 and preserves well carmine and coal-tar stains (haematoxylin stains 

 fade somewhat in it). The index of refraction is somewhat higher than 

 that of glycerin. Objects may be brought into it out of water. 



