THE MICROTOMIST'S VADE-MECUM

water (in which is placed a piece of camphor to prevent the
development of Infusoria), for twenty-four to seventy-two
hours, and   stained with   the author's carmine solution,         W V
Formula No. 55. They are dehydrated in baths of alcohol of
gradually increasing strength, cleared in " a somewhat resi-
nous " turpentine, and mounted in solution of dammar in
turpentine.                                                        COM
560. Spinal Cord (Krause's methods ').-After having, in
the course of his researches on the ventriculus terminalis,
tried all the known methods of preparation, Krause recom-
mends the following as being the safest:                           must
The fresh cord is hung up in a large cylinder full of            must
Miller's liquid; the lower end has a small weight attached to      Is
it, to avoid torsions which are otherwise caused by the elastic    o
fibres of the membranes.      After twenty-four hours, the         Pia
Miller's liquid is changed for 1 per cent. chromic acid,           tices
which is changed for fresh on the fourth day. A few days
later (when the cord appears hard), the chromic acid is
removed by means of water, and the cord put into spirit,
followed by absolute alcohol, which must be changed at least
twice. Imbed in paraffin; the sections either pass through
carmine, alcohol, oil of cloves, into Canada balsam, or simply     ion
through benzol, or Bronner's " Fleckwasser," and Canada             folk
balsam. (" Fleckwasser " appears to be a preparation of            lor
xylol.)                                                            for
561. Nervous Centres (Hamilton's method2).-The author             hit
objects to the use of chromic acid for hardening, on account        It
of the uncertainty of its action, some parts hardening well,
others becoming brittle, discoloured, and totally useless for      incd
purposes of research; whilst it cannot be employed for large        an u
masses of tissue without hardening one part more than               hen
another. He recommends the following procedure:
Take a fresh brain, and make a series of incisions into          al,
I Ibid., xi (1875), p. 226.                               r
2 'Journ. of Anat. and Physiol.,' xii (1878), p. 254.

350