608 
SUMMARY OF CURRENT RESEARCHES. 
a long time in vessels of yellow glass, although it is better that it should 
be made fresh before use. The injection is made either with an ordinary 
syringe with a fine platinum needle, or by means of an apparatus with 
continual pressure. When the injection is made, a cube at the centre 
should be marked off with a razor and placed in strong alcohol. After 
changing the alcohol as often as necessary, the piece should be cut into 
sections and these submitted to the action of acetic or formic acid, or 
other reagents, stained or not, and mounted in glycerin or Canada 
balsam. The author finds that the double action of osmic acid and 
nitrate of silver gives excellent preparations. The lymphatics are seen 
with great distinctness. 
Fig. 99. 
Influence of Osmic* Acid on the Preservation of Nuclear Struc- 
tures.* — Dr. B. Rawitz observed that the nuclei in the peripheral parts 
of the Salamander’s testis, treated with the chrom-osmio-glacial acetic 
acid mixture, differed from those in the central portion. He interpreted 
this as a nuclear disruption due to the violent action of the osmic acid. 
Flemming has denied the justice of this interpretation, Rawitz maintains 
his position and notes the differences observable when weak and strong 
solutions are used. But he allows that it is still a case of opinion 
against opinion. 
Criticism of Fixing Methods.! — Prof. A. Fischer points out some 
of the pitfalls of technique. Chemical reaction on the part of the tissue 
to be fixed, which is not always neutral or alkaline, is apt to give 
granular precipitates or coagulations, and these 
artificial products may often be mistaken for 
“ chromatin ” and other formed substances. But 
his cautions must be read in detail to be rightly 
appreciated. 
(6) Miscellaneous. 
New Oil-bottle.t — Herr H. Horne has de- 
vised an oil-bottle intended for microscopical 
purposes and so constructed as to prevent the oil 
from running over. The bottle, made of glass, 
holds 15-20 ccm. The upper part of the neck 
is expanded into a funnel-shaped lip d. The 
stopper is a glass rod with a spherical expansion 
at the junction of the handle with the dipper. 
This ball c must be of such size and so care- 
fully fitted that it only just rests on the junction 
of the lip d with the vertical part b of the neck. 
The dipper part of the stopper ends in a small 
ball e. 
Geotropic Chamber.§ — Prof. J. Sachs de- 
scribes a chamber in which the geotropic pheno- 
mena in the growth of plants can be observed 
and recorded without being disturbed by lielio- 
tropism. The image of the growing plant is thrown on to a ruled 
plate, and observed by a telescope fixed at a distance of 3-4 m. 
* Anat. Anzeig., x. (1895) pp. 777-80. f Tom. cit., pp. 769-77. 
% Centralbl. f. Bakteriol. u. Parasitenk., l te Abt., i. (1895) p. 418 (1 fig.). 
§ Flora, lxxx. (1895) pp. 293-302 (3 figs.). 
