536 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
The best stains are carmine and haematoxylin, or eosin, iodine-green, 
and fuchsin. Other anilin dyes, as gentian-violet, are not suitable. 
The preparations should be dehydrated in 80 to 85 per cent, spirit, aud 
then cleared up with creosote, or with a mixture of equal parts of 90 per 
cent, alcohol and creosote. They are then mounted in balsam, after 
having first passed through xylol. 
Although this method may appear complicated, in reality it saves 
a great deal of time. 
Surface Deposits in Golgi’s Method.* — Sig. P. Samassa, in criti- 
cizing Sehrwald’s method for preventing surface deposits in sections 
treated by Golgi’s method, j points out that in the original method of Golgi 
these surface deposits are considerably less. Hence, as in the latter no 
cover-glass is used, it is an obvious inference that the pressure of the 
glass sets up diffusion currents, whereby the precipitate is scattered over 
the section, and renders it often quite useless. The diffusion process 
is aided by the evaporation of the solvent. In the uncovered method, 
owing to the large area exposed to evaporation, these diffusion currents 
are not so likely to occur with such violence as when confined between 
two rigid layers. 
Staining Elastic Fibres and the Corneous Layer of Skin.} — 
Herr A. Eoppen, in a continuation of the technique of staining elastic 
fibres, § recommends a double staining, which may be either diffuse or 
nuclear. 
For diffuse staining the following solution is used : — Carmin optim. 
1 • 0 is dissolved in 50 ccm. cold water, then 5 ccm. liq. ammon. caust. is 
added, and the whole allowed to stand for two days. It is then filtered, 
and of the filtrate 1 drop is used to 20 ccm. water. The sections remain 
therein for twenty-four hours, and are then stained a diffuse red. 
Staining of the nuclei and protoplasm. — (1) Weigert’s picrocarmine 
stain is made by adding to the above solution 50 ccm. of a saturated 
aqueous solution of picric acid. This solution, which should be filtered 
before and after use, stains in from two minutes to several hours. 
(2) Grenacher’s alum-carmine is made by boiling together for 15 minutes, 
and then filtering, carmine 1*0; alum 5*0; water 50*0. 
The advantage of using these preliminary stains is that the subsequent 
decolorizing is extremely rapid. 
Decolorizing Preparations over-blackened by Osmic Acid.|| — The 
method of decolorizing objects over-blackened by osmic acid by means 
of peroxide of hydrogen was, says Dr. E. Overton, first introduced by 
Fol, but is so little practised that it merits a word in its favour. The 
following solution, which should be prepared every time, is recommended 
by the author : — Commercial peroxide of hydrogen 1 part ; alcohol (70-80 
per cent.) 10-25 parts. The removal of the osmium is completed in a 
few minutes, and the preparations stain excellently. 
Staining Sections of Botanical Preparations.^ — Dr. A. Zimmermann 
gives a short description of some methods for staining botanical pre- 
* Zeitschr. f. Wiss. Mikr., vii. (1890) pp. 26-8. f See this Journal, ante , p. 410. 
X Zeitschr. f. Wiss. Mikr., vii. (1890) pp. 22-5. § See this Journal, ante, p. 410. 
|| Zeitschr. f. Wiss. Mikr,, vii. (1890) pp. 10-12. % T. c., pp. 1-8 (1 fig.). 
