From _lung plague_ it is distinguished by the suddenness of its attack and rapidity of its progress to a fatal issue; by the usual coincidence of skin and bowel lesions, while the lung plague affects the chest only; by its communicability to pigs, sheep, pigeons, and even horses, which are all immune from lung plague; and by the usual absence of lung lesions of different ages, which are so characteristic of lung plague. The abundance in the blood of the cocco-bacillus with bipolar staining in hæmorrhagic septicæmia is characteristic. _Lung plague_ spreads slowly to exposed cattle, but spares all other domestic animals. From _Rinderpest_ it is differentiated by the history of its advent, by the presence of the surface œdematous swellings, by the absence of the whitish epithelial concretions on the mouth or vulva, and of the deep dark portwine discolorations of the mucosæ of the mouth, rectum and vulva, and by the fact of its inoculability on domestic animals generally. Rinderpest spreads rapidly to all exposed ruminants, but spares pigs, rabbits, Guinea pigs, horses and birds. From _malignant œdema_ it differs in its inoculability on the surface in place of subcutaneously only, in the presence of the cocco-bacillus in the blood during life, whereas in malignant œdema the germ is confined to the local lesion, in the absence of crepitation, which may be present in the swelling of œdema, in the greater facility with which cultures can be made of the septicæmic cocco-bacillus and in the absence of gas production in such cultures. The malignant œdema comes from a single accidental deep inoculation from almost any rich soil, and is not a malady spreading widely and generally on given limited damp, rich lands which have become infected. Finally the cocco-bacillus of septicæmia hæmorrhagica is found singly in the blood or exudate, whereas the microbes of malignant œdema may be found in form of sporeless filaments intermingled with the bacilli. _Mortality._ The hæmorrhagic septicæmia of cattle cuts off from 50 to 80 per cent. of the animals attacked. _Prevention._ The first consideration is to isolate and kill all the affected animals, to destroy the carcasses by burning or boiling and to burn or disinfect all objects that may have become contaminated. The buildings, yards, and fences, must be disinfected, and as the bacillus is very resistant a solution of corrosive sublimate and sodium chloride, a drachm of each to the gallon of water may be freely used after thorough cleansing. Or a whitewash containing ¼ lb. chloride of lime to each gallon may be substituted. Feeding and drinking troughs may be burned. Manure may be freely treated with sulphuric acid. Infected fields should be closed for years and if possible drained.