Specimens for laboratory examination.

Appx. XXI.

       As soon as dehaemoglobinization is complete, drain off the
fluid by tilting the slide. Next, flood the slide with methyl
alcohol. Allow to remain on for five minutes. The film
is now fixed.

       Drain off the methyl alcohol and wash the film very thoroughly
in distilled water. Every trace of acid must be removed
from the film, or the subsequent staining will be unsatis-
factory.

       Stain the film with Giemsa's stain or Leishman's stain, one
drop to one c.c. of distilled water, for 10 minutes. Differ-
entiate in distilled water. Do not blot the film, but allow
it to dry in air, placing the slide tilted against any vertical
surface, with the film side downwards to protect it from
dust.

       Examine with the 1-12th-in. oil immersion lens and a fairly
high, eg., No. 6 ocular. The leucocytes are seen to be
evenly scattered, field by field, over the half-inch square,
which can be rapidly examined for malaria parasites,
L. donovani, etc. As contrasted with control thick films
for healthy blood, the leucopenia of kala-azar at once
becomes most strikingly apparent.

PUS FILMS FOR MICROSCOPICAL EXAMINATION.

       23. These films should be prepared in the same manner as their
blood films(see para. 21).

       In preparing films for examination for the gonococcus, the sample
of pus should be collected on the patient's rising in the morning and
before he has urinated.

D. RULES FOR PRESERVING PACKING, AND DESPATCHING
SPECIMENS TO CHEMICAL EXAMINERS FOR ANALYSIS.

       1. The suspected viscus or other materials to be sent for examination
should be enclosed in a glass bottle or jar, fitted with a stopper or sound
cork.

       2. If the material sent is liable to decomposition, it should invari-
ably be preserved by one of the following methods:—

          (i) In cases of suspected poisoning in man, other than alcoholic
poisoning, the material sent should be immersed in spirit
of wine. The spirit should be sufficient in quantity to
cover the material immersed in whatever position the vessel
containing it may be held, and should not bear a less
proportion to the bulk of such material than one-third.
Care should be taken that common bazar spirit is not used.

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