ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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spermatozoa in the air-bubbles on the surface of the Farrant. The 
modus operandi is as follows : — A drop of Farrant is placed on the slip. 
A small quantity of the spermatozoa in 1;^ per cent, corrosive sublimate 
is dropped from a pipette on the Farrant. The cover-glass is lowered 
horizontally on to the spermatozoa, and if there are no air-bubbles 
visible to the naked eye, the cover-glass is lifted and again allowed to 
fall flat on the spermatozoa. The superfluous fluid is drawn from the 
edge of the cover-glass with a piece of blotting-paper. The mount is 
placed in a drying cabinet for some hours until the Farrant is set quite 
hard, and is then secured by two coats of Hollis.” 
Methods for making Permanent Preparations of Blood.* — Dr. U. 
Rossi communicates two methods by means of which he obtains per- 
manent preparations of blood. (1) In a glass vessel is prepared a 
strongish and recently filtered solution of methyl-green. Another 
vessel is filled with one-third distilled water, one-third osmic acid 
(1 per cent.), and one-third of the foregoing solution. The mixture 
should be quite clear, and of an emerald-green colour. One drop of 
this mixture, which is at the same time fixative and staining, is placed 
on a slide. Then a glass rod just smeared with the staining solution is 
dipped in the heart’s blood of a recently killed animal, and this drop of 
blood mixed with the drop of the methyl-green solution on the slide. 
The preparation, protected from dust, is left in a moist atmosphere for 
about half an hour. At the end of this time the preparation is treated 
with a minute drop of acetic acid, all the various ingredients being care- 
fully mixed together with the quill-point which has carried the acetic 
acid. The preparation is then covered over, and glycerin in very small 
drops placed along the edge of the cover-glass, under which it slowly 
runs. 
(2) Blood obtained directly from the heart of some small mammal 
is allowed to fall into a watch-glass containing osmic acid of 1-lJ^ per 
cent. The mixture having been well shaken up, is poured into a little 
tube and left for 24 hours. At the expiration of this time the blood is 
deposited at the bottom, and the osmic acid is then siphoned off or 
removed by means of a piece of cotton thread, one end of which dips 
into the fluid, but so as not to touch the blood, and the other into an 
empty tube. When the acid has been removed the blood is washed two 
or three times with distilled water, this being removed in the same way 
as the acid. The blood is then stained with alum-carmine to which 
has been added acetic acid in the proportion of 1 per cent, by volume of 
the carmine solution. The blood is then washed again, and next treated 
first with rectified spirit and afterwards with absolute alcohol. A drop 
of this blood is removed with a pipette to a slide, and when the spirit has 
evaporated is treated with carbol-xylol and then mounted in dammar. 
Effect of Galvanic Current and other Irritants on Protista.t— 
Dr. M. Verworn, in studying the effect of galvanism upon certain 
* Zeitschr. f. Wiss. Mikr., vi. (1889) pp. 475-7. 
t Pfliiger’s Archiv f. d. Ges. Physiol., xlv. (1889) pp. 1-36 (2 pis. and 6 figs.) ; 
xlvi. (1889) pp. ' 267-383 (3 pis. and 5 figs.). ‘ Psycho-physiologische Protisten- 
Studien,’ Jena, 1889, 8vo, 220 pp. and 6 pis. Cf. Zeitschr. f. Wiss. Mikr., vi. (1889) 
pp. 496-50 (3 figs.). 
