_Synonyms._ The earlier designations were mostly drawn from the red or black discoloration of the skin and mucosæ and applied indiscriminately to the other forms of hæmorrhagic septicæmia which we now differentiate as erysipelas (rouget, Rothlauf) and swine plague. They included _measles_, _erysipelas_, _scarlatina_, _red soldier_, _purples_, _blue sickness_, _carbuncular fever_, etc. Others basing their nomenclature on the prominent intestinal lesions, etc., designated it _typhoid fever_, _pig typhoid_, _typhus_, _carbuncular gastro-enteritis_, _pneumo-enteritis_, and _diphtheria_. Even in Europe while the _pig erysipelas_ (_rouget_, _Rothlauf_) is now recognized as a distinct disease there is no clear distinction made between _hog cholera_ and _swine plague_. In England we find these more or less confounded under the names of _swine fever_, _swine plague_ and _hog cholera_, and on the continent of Europe under those of _schweineseuche_ and _schweinepest_, or _pneumo-enteritis infectieuses_. Differences in different epizoötics or outbreaks are recognized, and the field is left open for the future identification of different forms of this common group of swine fevers, but the existence of constant bacteriological distinctions are not always insisted on, as we do in the United States in the case of the two great leading types _swine plague_ and _hog cholera_. _History._ Definite history of this disease may be said to begin with the discovery and demonstration of the actively motile hog cholera bacillus by the U. S. Bureau of Animal Industry in 1885. Yet in the history of animal plagues, even in early times, deadly epizoötics are described which undoubtedly represented one or other of the contagious affections of modern times. Among the more definite may be named a destructive gastro-enteritis (magen seuche) in Germany in 1817, a pleuro-pneumonia in France and Bavaria in 1821, a cholera with blotching of the skin (morbus niger) in Ireland, and an erysipelas in pigs in France and Switzerland in 1836, and in Ohio in 1833, there was a fatal affection afterward recognized as hog cholera. Writers conjecture that it was imported into America from Europe in improved pigs, and from one European country to another in the same way, but we have no absolute proof of times and shipments and their immediate effects, so that these theories are but more or less reasonable deductions from the familiar extensions of the disease in more recent cases. Under the great commercial activity of the latter half of the 19th century, the active movements of animals by canal, steamboat and rail, and the massing together in one market of many animals drawn from widely different sources, hog cholera has made extraordinary extensions on both sides of the Atlantic, until Friedberger and Fröhner pronounce the schweineseuche and schweinepest the most widely disseminated and dangerous of swine epizoötics, and Dr. Salmon estimates the losses in the United States at