CYTOLOGICAL METHODS

CHAPTER XXXIII.
CYTOLOGICAL METHODS.
483. Cell-division (Peremeschko's methods ').-Tbe objects
studied were the tissues of the tail of larve of Triton cristatus.
The reagents used were: Gold chloride, - to J per cent.;
osmic acid, 1 to J per cent.; silver nitrate, - per cent.; and
absolute alcohol. The alcohol is most to be recommended.
For staining, humatoxylin, fuchsin, and neutral solution of
carmine were used. Tissues may be left for a quarter of an
hour in absolute alcohol, stained with one of the above-men-
tioned stains and mounted in glycerin or dammar.
In the living animal the epithelial cells and nuclei (in the
state of repose) are so transparent as to be invisible in the
natural state. They may, however, be brought out by cura-
rising the larva; or still better, by placing the curarised larva
for half an hour in 1 per cent. chloride of sodium solution.
Normal larvoe may be used for the study of the active state
of the nucleus, but much time is saved by using curare.
Curare.-Dissolve 1 part of curare in 100 parts water, and
add 100 parts of glycerin. Of this mixture add from 5 to 10
drops (according to the size of the larva), or even more for
large larve, to a watch-glassful of water. From half to one
hour of immersion is necessary for curarisation. The larvoe
need not be left in the solution until they become quite
motionless; as soon as their movements have become slow they
may be taken out and placed on a slide with blotting-paper.
I 'Arch. Mik. Anat.,' xvi (1879), p. 437.

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