ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 11^ 
Examination of Hirudo medicinalis.* — Dr. J . M. Croockewit killed 
liis leeches with 96 per cent, alcohol, and put them into alcohol, to which 
was added picric acid to dissolve the carbonate of lime in the teeth, for a 
day ; the best staining results were got with Bohmer’s haematoxylin. 
Mitosis in Ova of Ascaris.j — Herr V. Herla found the best fixative 
to be a mixture of 1 part of glacial acetic acid with 5 parts of absolute 
alcohol. His stain was a mixture of the following (parts by weight) : — 
Yesuvin *25, malachite-green *25, distilled water 100, glycerin 10. 
Division of Amoeba.f — Dr. F. Schaudinn fixed Amoebae with hot 
concentrated sublimate, or in platinum chloride-osmo-acetic acid 
(Herrmann), or in Kleinenberg’s picro-sulphuric acid. He washed 
them in the first instance with 63 per cent, iodine-alcohol, in the 
second with water, in the third with 63 per cent, alcohol. Those fixed 
with sublimate were best stained with iron-alum and hsematoxylin 
(Benda-Heidenhain), but Ehrlich’s haematoxylin, &c. yield good results. 
(3) Cutting-, including: Imbedding- and Microtomes. 
Micro-Aquarium which can also be used for Paraffin Imbedding.§ 
— Dr. F. Schaudinn has devised a small cover-glass aquarium to replace 
the Cori stage-aquarium when small organisms not visible with the un- 
aided eye are to be examined. 
In an ordinary slide is cut a rectangular opening a which reaches 
about up to the middle of the slide. On each side of this, cover-glasses 
Fig. 20. 
b are cemented by Canada balsam, as seen in the figure (fig. 20). On 
both sides of the cover-glasses small strips of glass c are cemented. In 
this way a small aquarium is obtained into which water and creatures 
can be introduced by means of a pipette. The slide can be used in the 
horizontal position, since owing to capillarity no water can flow out. 
For keeping the water fresh, green algae can be used or fresh water 
can be introduced by means of a woollen thread. 
For the observation of living organisms the aquarium offers the 
advantage that even with high magnification the whole space can be 
easily examined. 
Organisms which have fastened themselves on the walls of the cover- 
* Tijdschr. Nederl. Dierk. Vereen, iv. (1894) pp. 297 and 8. 
t Arch. Biol., xiii. (1893, published 1894) pp. 423-50 (5 pis.). 
X SB. K. Preuss. Akad., 1894, pp. 1029-36 (5 tigs.). 
§^Zeitschr. f. wiss. Mikr., xi. (1894) pp. 326-9. 
