456 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(5) Mounting-, including Slides, Preservative Fluids, &c. 
Method for Exhibiting Polyzoa.* — Prof. M. Hartog recommends 
that Polyzoa and other small animals should be mounted in a hanging 
drop of water on the under side of the cover-glass, luted on to a cell 
of paraffined millboard. In this way evaporation is prevented, so 
that Lopliopus and other Polyzoa may be preserved for 48 hours. 
Fluorides of Sodium as Fixatives and Preservatives.f — Herr G. 
Marpmann calls attention to the fixative and preservative properties of 
the fluoride and bifluoride of sodium. Solutions of both salts attack glass, 
the polish of which is destroyed. They are antiseptic, and are more 
agreeable to work with than either formalin or sublimate. The bi- 
fluoride solution is miscible with gelatin solutions. 
The following formulae are given : — 
For fixing lower organisms: sodium fluoride 0'5 part; sodium 
bifluoride 2*0; water 100. 
For fixing animal tissues : sodium fluoride 5 parts ; sodium chloride 
5-10 ; water 100 ; or sodium bifluoride 5, water 100. 
For mounting reptilia : sodium bifluoride 5 parts ; glycerin 50 ; 
alcohol 100 ; water 400. 
In the foregoing, the colours of snakes and frogs are well kept, 
and the animals retain their elasticity better than in sublimate or 
formalin. 
For preserving organs, &c. : sodium bifluoride 5 parts ; sodium 
chloride 30 ; water 300. 
For preserving embryos : sodium bifluoride 4 parts ; formol 1 ; water 
100 . 
For hardening glands and central nervous system : Muller’s fluid 
100 parts ; water 100 ; sodium bifluoride 5 ; formol 5. In 4-5 days the 
objects are sufficiently hardened, and should then be treated with alcohol. 
Demonstrating Hsemogregarina Stepanowi.f — M. A. Laveran re- 
commends the following method for examining the endoglobular para- 
sites of Cistado europsea. Blood is smeared on a slide, and when dry 
is immersed in picric acid for 20-30 minutes. It is then washed in 
water and stained. Flemming’s fluid fixes equally well, but the staining 
is not so good. The staining solution used was as follows : — Saturated 
aqueous solution of methylen-blue 2 ccm. ; distilled water 4 ccm. ; aque- 
ous 1 per cent, solution of eosin 8 drops. The mixture must always be 
freshly prepared. The objects remain in the solution 6-12 hours, and, 
after having been washed in water, are rapidly dehydrated in absolute 
alcohol and mounted in balsam. 
Toluidin blue and carbol-thionin also give very useful preparations. 
Methyl Salicylate in Histological Technique^ — M. F. Gueguen 
recommends the introduction of methyl salicylate into histological 
technique. It is a colourless fluid with an aromatic odour and a refrac- 
* Illustd. Annual of Microscopy, 1898, p. 48. 
t Zeitschr. f. angew. Mikr., v. (1899) pp. 33-7. 
j C.R. Soc. Biol., v. (1898) pp. 885-9. See Zeitschr. f. wiss. Mikr., xv. (1899) 
p. 461. 
§ C.R. Soc. Biol., v. (1898) pp. 285-7. See Zeitschr. f. wiss. Mikr., xv. (1899) 
pp. 455-6. 
