The gastro-intestinal disorders caused by these poisons; (it may be botulism from stale or decomposing flesh, fish or fowl, the poisoning by mouldy bread or musty grain, or meal, or by the toxins of the many and varied saprophytic fermentations), often prove as deadly as outbreaks of genuine hog cholera, and are habitually mistaken for them. They do not, however, as a rule extend beyond the particular herd which has been exposed to the faulty management, and introduce no risk of a general spreading infection. The careless owner suffers and adjacent herds escape, unless exposed to similar causes. But if the hog cholera germ is present these pave the way for its destructive advance and tend to enhance the mortality. It may even be that the combination of the two factors is a condition of the eruption of a severe attack. The faulty feeding or food or poison by itself could be resisted, and the comparatively non-virulent hog cholera bacillus might have been resisted, but with the weakened system and digestive apparatus, the microbe finds a specially inviting field in which it can multiply destructively, and where it can gather a virulence which will enable it to invade and sweep away herd after herd in a deadly epizoötic. I may add, as a prominent factor in the great modern extensions of hog cholera, the habitual aggregation of swine in large herds. This with the rapid steam transit of modern times, and the great aggregations of hogs in one common market, probably contributes more than anything else to the extraordinary diffusion of the infection. By accident, purchase or otherwise, a large herd becomes infected, and the owner, knowing that delay is ruin, at once ships the apparently healthy animals to market; these infect anything they or their excretions come in contact with; if sold in smaller lots they carry infection into every locality where they go, and along the route; if sold for slaughter, they still diffuse infection through the herds that receive their butcher and kitchen trimmings.