406 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
removal from this last reagent they are again washed with distilled 
water, then alcohol, after which they are imbedded in celloidin or 
paraffin. 
Preserving Larvae of Crinoids.* — Dr. 0. Seeliger found that of the 
various methods by which he preserved the larvae of Crinoids, sublimate 
solutions were the best ; not only was the external form truly preserved, 
but the histological details were in a good state. In the later stages, 
when calcareous plates begin to be deposited, these solutions could 
not, of course, be used. For the cleavage stage, 1/50-1/60 part of con- 
centrated acetic acid may with advantage be added to the sublimate ; 
the addition of 1/10 per cent, chromic acid made the embryos rather 
brittle, and they stained less well than when it was not used. To pre- 
serve the calcareous plates, absolute followed by 80 per cent, alcohol 
should be used. 
Almost all the embryos and larvse were stained slightly before im- 
bedding in borax-carmine; this makes them more easily visible, and 
notwithstanding their small size they are not so easily lost in paraffin. 
The sections were most satisfactorily stained with Grenadier’s acetic 
haematoxylin solution ; if they colour too deeply they should be placed 
in weak acid alcohol. Some observations were also made on teased 
preparations. 
Demonstration of Living Trichinse.f — Dr. A. S. Barnes recommends 
that a piece of trichinized muscle, about the size of a pea, be placed in 
a small bottle, containing a solution of 3 grains of pepsin, 2 drachms of 
water and 2 minims of hydrochloric acid. If this be kept at the tem- 
perature of the mammalian body, and the fluid be now and again shaken, 
the meat will, in about three hours, be dissolved, as will also the cysts 
which contain the Trichinae. The fluid is next to be poured into a 
conical glass, so as to allow the Trichinae to settle at the bottom. 
They may then be drawn out by a pipette, and the contents placed in a 
large glass cell. Put the cell under a dissecting^ Microscope ; pipette 
out the Trichinae and place them in clear water. Again pick out the 
worms and place in a drop of pure water in the centre of a glass cell 
or live-box. Put on a cover and seal with white vaseline. Examine 
on a hot stage. If a permanent mount of isolated worms be wanted, 
use a drop of glycerin instead of water. 
Observing and Dissecting Infusoria in Gelatin Solution. — The 
procedure adopted by Mr. P. Jensen consists in placing the organisms 
in a weak solution of gelatin. A 3 per cent, solution is the most satis- 
factory, and this is made by dissolving 3 grm. gelatin in 100 ccm. of 
water with gentle heat. At a temperature of 18° to 19° C. this solution 
sets to a Arm jelly. The solution can be kept in a flask stopped with 
cotton-wool, or, better still, after sterilizing thrice at about 80°. Large 
infusoria, like Paramecium aurelia and TJrostyla grandis, when immersed 
in this jelly and placed under a cover-glass, no longer move. If the 
jelly be thinned down by adding an equal bulk of water, it becomes 
* Zool. Jalirb. (Anat. u. Ontog.), vi. (1892) pp. 168-72. 
t Amcr. Mon. Micr. Journ., xiv. (1893) p. 101. 
X Biol. Centralbl., xii. (1892) p. 556. See Zeitschr. f. wiss. Mikr., ix. (1893) 
pp. 483-5. 
