558 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
be clamped before the test-tube is removed for incubation. In a 
similar way any of the test-tubes may be filled at any time during the 
filtering process. 
The results obtained from filtering impure water by means of the 
Chafnberland bougie were not at all satisfactory, for though the water 
which flowed through at first was germ-free, it soon showed con- 
tamination, and that therefore the porcelain filter is unable to deprive 
dirty water of its germs. 
(2) Preparing- Objects. 
Eserin in Protistological Technique.* * * § — Sig. P. Longhi finds that a 
mixture of 1*10 per cent, of eserin sulphate to 10 ccm. of which one 
drop of a 1 per cent, sublimate solution is added, is of excellent service 
for all Protista and especially for Rhizopoda. The general form is 
retained, the separate parts of the organism remain clearly apparent, the 
pseudopodia and cilia are fixed in their natural position, and there is no 
interference with hardening or staining. 
Preserving Achlorophyllous Phaneragamous Parasites and Sapro- 
phytes, j — Prof. E. Heinricher finds that the troublesome blackening of 
certain plants, e.g. Lathrsea , which occurs when preserved in spirit, 
or by pressure, may be avoided by steeping them in boiling water and 
continuing the boiling for about a quarter of an hour. After this 
they are transferred to spirit or pressed, when it will be found that 
there is scarcely any blackening at all. 
Nor are these the only advantages offered by this simpler procedure, 
for it is well known that boiling water acts as a fixative, and hence the 
method is advantageous for anatomical purposes. 
Preparation of Vegetable Objects. if — Herr W. Bieliajew recom- 
mends the following mode of treatment of microtome-preparations. The 
fixing is effected by Perenyi’s fluid, 3 pts. 0 5 p.c. Cr0 3 , 4 pts. 10 p.c. 
HN0 3 , 3 pts. alcohol. After fixing and staining, the object is gradually 
transferred to absolute alcohol and pure xylol, and then placed for a 
day in a saturated solution of paraffin in xylol at a temperature of 35° ; 
finally warmed to 47°, and then placed in paraffin melting at 45°. The 
object is simply placed on the slide which has been moistened with dis- 
tilled water, and the water allowed to evaporate. 
Objects which contain no vacuoles, such as spermatozoids and their 
mother-cells, are first stained on the slide, and some gum arabic added 
and allowed to dry ; and the object becomes then so firmly attached 
that both the fixing material and the gum can be washed away without 
disturbing it. 
Isolation of Living Protoplasts.§ — Herr J. af Klercker isolates 
protoplasts by first plasmolysing pieces of leaf or sections of larger 
organs to such an extent that the protoplasts become detached on all 
sides from the cell-wall. The sections are next cut to pieces in the 
plasmolysing solution, when some of the contracted protoplasts escape 
* Boll, dei Musei Zool. e Anat. Comp, della R. Univ. Genova, 1892, No. 4. See 
Zeitsclir. f. wiss. Mikr., ix. (1893) p. 483. 
f Zeitsclir. f. wiss. Mikr., ix. (1893) pp. 321-3. 
X Scripta Botanica, 1892, 12 pp. See Bot. Centralbb, liv. (1893) pp. 105 and 6. 
§ Ofvers. K. Vetensk. Akad. Forh. Stockholm, 1892, pp. 463-74 (8 figs.). 
