Although the organism is readily seen without being first stained, some may prefer to stain it, and we therefore give the most easy and at the same time most effectual method of carrying out this procedure.
"Make a thin smear of pus from the suspected wound, ulcer, or pustule on a cover glass or slide, fix it in the ordinary manner by passing it three times through the flame, and then proceed to stain with the following preparation: -
"Leave the stain on for about five minutes, then run it off, removing the superfluous stain by waving it for a moment or two in water, and put on: -
Iodide of Potassium
"This fixes the stain in the organism. After leaving it in for two or three minutes run it off and treat with alcohol, which takes the stain out of everything except the various organisms which have taken it up, in fact it will begin to remove it from the cryptococci also if left on for more than a few seconds.
" Having now decolorized put on the following counter stain: -
Saturated Solution of Vesuvine (Bismarck Brown), and after having left it on for about three minutes run it off, wash in water, and dry. The specimen is now ready to be examined under the microscope, or may be mounted in Canada Balsam." (Pallin.)
Any wound on any part of the surface of the body with which the virus may be brought into contact offers an opportunity for infection. A brush on the fetlock joint or a crack in the heel will account for its ofttimes occurrence on the hind limbs, a broken knee or a less marked injury to some other part suffices to explain its less frequent occurrence in the fore-legs. Injury to the face, the poll, the withers, or back by the harness will expose the animal to infection, as will also wounds following upon castration and breaking of abscesses in strangles.