The final tests are, however, by the microscope and inoculation. To discover the bacillus a power of 400 to 500 diameters is desirable. From the living animal take a drop of blood, exudate, or hæmorrhagic extravasation, make a thin film on a cover glass by drawing across it the straight edge of another one, dry the film, then pass it three times through the alcohol flame film downward, stain in anilin dies, or clear with acetic acid and examine. The bacillus is large (5 to 20µ by 1 to 1.5µ), nonmotile, of uniform thickness throughout, and sharply cut off at the ends. The bacillus of blackquarter is shorter, often club-shaped because of a spore in one end, has rounded ends, is flagellate, motile and gasogenic. That of malignant œdema is much thinner, has rounded ends, sluggish movements and is gasogenic. The bacillus subtilis (hay bacillus), is short, thick, with rounded ends each bearing a flagellum and is motile. The proteus vulgaris (common septic saprophyte) is small, short, with rounded ends, and very active movements. If the subject is dead we may examine the blood, or the scraping from the cut surface of the spleen, liver, kidney, congested lymph gland or other part bearing the lesion. If we find in the carcass exudates gelatinoid or bloody (especially the latter), petechiæ, dark, uncoagulated blood, brightening little on exposure, blood gorged spleen, congested or hæmorrhagic condition of one or more internal organs, muscle or connective tissue, (particularly of the lymph glands), if the muscles of the loins, quarters, thighs, diaphragm or elsewhere, are soft, as if parboiled or salmon-colored, clammy, friable, or if reddish, yellowish, brownish, with petechiæ, and capillary embolism the case will require critical examination. If the first examination fails to show the bacilli, repeat it from different lesions until thoroughly satisfied of their absence, or until another cause for the condition has been discovered. The blocking of the capillaries with bacilli in the various lesions is a most important point, never to be overlooked. In case of uncertainty, inoculation of a Guinea pig, mouse or rabbit should be made. The blood or scraping from the seat of a lesion is made into an emulsion if necessary, and injected subcutem. A single bacillus will destroy a mouse or Guinea pig in from one to four days, and the blood shows the characteristic bacilli.