258 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Fixing-Material for Meristem.* * * § — Herr G. Rosen recommends the 
following : — A mixture of 10 gr. sublimate, 300 gr. distilled water, and 
3 gr. glacial acetic acid; for Ferns, a mixture of 6 parts alcohol, 1 part 
glacial acetic acid, and 2 parts chloroform. As staining reagents he 
employs iodine-green-fuchsin and Heidenhain’s liflematoxylin-iron-alum 
in combination with Bordeaux R or Rubin S. 
Test for Cholesterins.f — M. E. Gerard gives the following test for 
distinguishing between animal and vegetable cholesterins : — If the 
former are treated with concentrated sulphuric acid, a yellow colour 
is produced, and a white precipitate on diluting with water ; while the 
latter are coloured red by sulphuric acid, and yield a green precipitate 
on the addition of water. 
Microscopical Examination of Meat for Tubercle Bacilli.:): — 
Dr. Morsy examines meat for tubercle bacilli by placing a small piece 
of a gland between two slides and pressing them firmly together. The 
films on the slides are then dried over the flame of a lamp. Upon the 
film are placed some cubic centimetres of carbol fuchsin, and the slide 
warmed for ten minutes. The fluid should not be allowed to become 
dry. The slide is then washed in water and afterwards decolorised in 
an acid mixture. When sufficiently decolorised the slide is washed 
again in water, and then contrast-stained with malachite-green. The 
preparation is again washed with water, then treated with absolute 
alcohol, and finally dried in the air. It may now be examined by just 
dropping on the surface a little cedar oil, no cover-glass being used. 
The tubercle bacilli appear as dark red thin threads, the tissues and 
cells and other organisms being green, except a diplococcus occasionally 
met with in tuberculous pus. This coccus cannot be confounded with a 
tubercle bacillus, partly on account of its shape, but partly also because 
it does not retain the red so well as the tubercle bacillus. 
The carbol-fuchsin solution is made as follows : 1 grm, of fuchsin is 
dissolved in 20 ccm. of alcohol, and then 5 ccm. of carbolic acid and 90 ccm. 
of water are added. The formula for the decoloriser is — hydrochloric 
acid 3*0, common salt 2*0, water 100*0, alcohol (90 per cent.) 500*0. 
The counter-stain is made by dissolving malachite-green 1 • 0 in 100 of 
alcohol and 100 water. 
Cocain in the Study of Pond Life.§ — Prof. H. N. Conser finds 
that the following method is suitable for fresh-water Bryozoa. Several 
-colonies are placed in a solid watch-glass with 5 ccm. of water, and as 
soon as the animals have expanded, 1 or 2 cgrm. of cocain are dropped 
on the edge of the water at two or three distant points. After about 
15 minutes, 1 per cent, chromic acid is poured into the watch-glass and 
left to act for half an hour or more, when it is replaced by water. In 
half an hour the process is repeated ; then alcohol is gradually added 
until it reaches about 80 per cent, of the immersion fluid. The free- 
swimming Rotifers readily succumb to the influence of the cocain, but 
.the family Melicertidae hold out a long time ; the quantity of cocain 
* Beitr. z. Biol. d. Pflanzen (Cohn), vii. (1895) p. 233. 
f Comptes Rendus, cxxi. (1895) p. 723. 
% Zeitschr. f. Angewandte Mikroskopie, i. (1895) pp. 71-4. 
§ Trans. Amer. Micr. Soc., xvii. (1896) pp. 310-1. 
