242 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
tion with distilled water, boiling for 2-3 minutes ; repeat the last treat- 
ment thrice. Wash with 1 per cent, solution of acetic acid, and finally 
with distilled water. The sections are then quite ready for staining. 
The author advises alkaline glycerin as a mounting medium, the mixture 
recommended being composed of glycerin 2 oz., distilled water 1J oz., 
solution of potash (B.P.) 1/2 oz. 
Preparing Central Nervous [System.* — Mr. H. J. Berkeley, when 
studying the lesions produced by the action of certain poisons on the 
cortical nerve-cell, adopted the following method of preparing and 
examining the brains. The cerehra are hardened in Muller’s fluid 
until the tissue is of sufficient consistency to admit of fairly thin sec- 
tions (about two weeks at room temperature). Pieces not more than 
3 mm. thick are then immersed in a mixture of 3 per cent, solution 
bichromate of potash 100 parts, and 1 per cent, osmic acid 30 parts, for 
2 or 3 days. On removal, the pieces are mopped up on blotting-paper, 
washed for a few moments in weak silver nitrate, and then transferred 
to a solution composed of 2 drops of 10 per cent, phospho-molybdic acid 
to 60 ccm. of 1 per cent, silver nitrate solution. 
This last solution must be prepared the moment before placing the 
brain tissue in it, and the pieces remain therein for 2 or 3 days ; if 
longer, a few drops of nitrate of silver solution must be added to prevent 
precipitation. Light does not affect the process unfavourably, though it 
is better to keep the jars covered up. In winter the solution should 
be kept at a uniform temperature of about 25° C. By this procedure the 
individual details of the component parts of the neuron are finer than 
in Golgi sections ; each element stands out clearly and distinctly ; the 
axons and their collaterals are clear, and not too numerously tinged ; 
and the gemmulce on the protoplasmic processes are fully and equally 
impregnated, and appear in their proper relations to the parent dendrite. 
Apparatus for Rapidly Fixing and Hardening Tissues.f — Prof. R. 
Thoma describes a simple apparatus made of tin-plate for rapidly hard- 
ening pieces of tissue, provided that their structure is not too fragile or 
delicate. It consists of an overshot wheel, the interior of which has six 
compartments for preparation glasses. The latter are fixed tightly by 
means of cotton-wool packing. The wheel is driven by water from a 
dropping apparatus capable of holding 10 litres of water. The author 
mentions a dropper of his devising which can be fitted on to the ordinary 
water-tap. 
(3) Cutting-, including: Imbedding- and Microtomes. 
New Microtome.* — The instrument invented by Dr. S. Yankawer 
consists of two parts, a stand and a movable right-angled piece. The 
stand is a triangular piece of metal across the base of which an oblong 
piece of glass is fixed. At the apex of the triangle is a , a small elevation 
with an excavation 1/8 in. in diameter and 1/8 in. deep. The bot- 
tom of the hole is on a level with that of the glass plate. One arm of 
the sliding piece e, /, g , is 7J in. long, the other 12 J in. long* 
[T * Johns Hopkins Hospital Rep., vi. (1897) pp. 1-108 (15 pis.), 
t Zeitschr. f. wiss. Mikr., xiv. (1897) pp. 333-4. 
% The Microscope, v. (1897) pp. 145-8 (2 figs.). 
