ar

394           THE MICROTOMIST'S VADE-MECUM
dissolved in serum   (which is a better solvent of it than         st'
water).                                                            adth
The stain appears to be concentrated in the fatty granules      Dot to
of the protoplasm. Nuclei and nucleoli remain unstained.           ii@
For this reason, the figures of nuclear division are very          let
clearly brought out in contrast with the surrounding stained       tel
protoplasm. Certes considers quinoldin an important help to       liero
the study of cell-division, conjugation, and other minute         9i9O4
phenomena of cell-life, in living cells.                           las
The reactions on tissues or Infusoria that have been killed       4
are of a quite different nature, and do not at present appear      led,
to be of any value.                                                aci1
In a later communication ('Zool. Anz.,' No. 84, p. 288           Is
(1881), Certes announces that solutions of 1-500,000 have         abteo
sufficient colouring power. He notes that the aqueous solu-       the
tions should always be prepared with spring-water, as distilled    chal
water is a poison for Infusoria.                                  with
Alcoholic solutions (in - alcohol) should be of 1-100,000       aheft
strength.                                                          yor
All solutions should     be kept in    the dark, as light       alt
decolourises them.                                                 Itshe
641. 1ethylen-Blue for Protozoa (Certes' method').-A             Is
drop of alcoholic solution is placed on a slide and allowed to     Mi
evaporate. When the evaporation is nearly complete, add a          takn
drop of the liquid containing the organisms. As soon as the        the
staining action is complete, which quickly happens, the drop       (As
must be caused to flow away from the spot where the crystals      tibta
are deposited, and may then be covered and examined.                di
Methylen-blue is an agent that stains living protoplasm.
642. Infusoria (Ge'za Entz's methods).-For fixing, any of      inste
the usual fixing solutions may be employed, but picro-             61
sulphuric acid is most to be recommended. Entz adds a few          olapt
drops of the liquid to a watch-glass containing the animals in
Ibid., 1882 (2me sem.), p. 464.
 'Zool. Anz.,' No. 96 (1881), p. 575.