488 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
logical structure and peculiarities of nucleoli in the cells of the central 
nervous system. Pieces of spinal cord, 0* * * § 5 centimetre thick, may be 
hardened in alcohol, or they may be first fixed in saturated solution of 
sublimate, or in commercial formol diluted to one-half, and then after- 
hardened in alcohol. 
The celloidin sections are immersed for 10 seconds in warm 1 per 
cent, aqueous methylen-blue solution, or in carbol fuchsin. The sections 
are decolorised in alcohol, and then placed in chloroform, which dissolves 
out the celloidin. After dehydrating in alcohol and clearing in cajeput 
oil, the sections are mounted in Canada balsam. 
By this method, while the nuclear mass remains unstained, the nucleoli 
or nuclear corpuscles are highly coloured, and show one centrally placed 
body, or several extremely small granules with no definite distribution 
and a crenated appearance. 
Bowhill’s solution * is also recommended as a good stain for demon- 
strating the nucleoli. 
Peroxide of Hydrogen in Microscopical Research.! — HerrR. Yolk 
recommends peroxide of hydrogen for killing motile and sensitive 
animals of minute size. One drop of three per cent, solution to 2 ccm. of 
water suffices for some Rotatoria, and 1 drop to 1 ccm. of water kills 
Anurese and other Loricata. The solutions should always be as weak as 
possible, especially as delicate species are damaged by the oxidising 
action of the stronger mixtures. When the animals are dead, the mix- 
ture must be replaced by water, or by water with 0 • 3 per cent, of salt. 
When washed the animals are fixed in the usual way. For objects which 
contain carbonate of lime the peroxide must be perfectly free from 
acid. 
Preparing Permanent Blood-Films. :£ — Herr A. Zielina prepared 
blood-films by receiving a minute drop of blood on one side of a cover- 
glass, and then distributing it over the surface by touching it with the 
edge of a slide which is drawn across the cover-glass from left to right. 
A clean edge is necessary for each film, and the wound should be 
wiped before taking the next drop. 
The films are dried in the air, and are fixed by drawing them eight 
or nine times through the flame. When cool they are stained for 
30 seconds in Nicolle’s one-third eosin (saturated alcoholic solution of 
eosin 50 ccm., 95 per cent, alcohol 100 ccm.). The superfluous stain is 
removed, and the preparation dried. The film is again stained in ripe 
Ehrlich lisematoxylin for 30-40 minutes. The cover-glass, film side 
downwards, is then suspended on water for a time. It is again stained 
with the one-third eosin solution for 30 seconds. After having been 
washed with water, it is dried, and mounted in balsam. 
How to examine the Blood and Diagnose its Diseases.§ — Dr. A. C 
Coles has, by producing a compact account of methods for examining the 
* See this Journal, ante , p. 244. 
t Zool. Anzeig., xix. (1896) pp. 294-5. See Zeitschr. f. wiss. Mikr., xiv. (1898) 
p. 469. 
X Zeitschr. f. wiss. Mikr., xiv. (1898) pp. 463-4. 
§ London, Churchills, 1898, 260 pp. and 6 pis. 
