CHOLERA ASIATICA.
Definition.—Cholera Asiatica is a mi asmatic, contagious disease transmitted mainly by human intercourse, but whose epidemic character depends upon out side conditions.
Origin and Transmission.—The origi nal seat of cholera is in India, where it most probably existed long before this century. In some parts, especially on the borders of the Ganges it is always en demic, being produced and entertained by special conditions of the soil, by the infection of the water, ete., and often giving rise to epidemic outbreaks under the influence of hig,h temperature, climatic variations, bad hygienic condi tions, certain winds, etc. The epidemics may propagate themselves either by land or by sea, through the great roads of commerce, being conveyed to other coun tries by caravans or by vessels, forming here and there many momentary, sec ondary centres. The agents of trans mission are persons infected with cholera or specific diarrhom, and the linen, clothes, etc., soiled with choleraic dejec tions, from such persons.
The land-route was followed by the first great epidemic of 1830 and 18-18 (the last reaching America), while the second prevailed in the epidemic of 1869 and of 1SS-I. -When the cholera pro ceeded by land, its course was slow and its steps easily marked, by its invading successively Afghanistan, Persia, the Caspian shores, Astrakan, Russia, and then turning toward the west of Europe and America. The epidemics trans mitted by sea generally made their first appearance at Mecca or other parts of the Red Sea, and thence were propagated to Egypt, Or reached Beyrouth, Constan tinople, Marseilles, Toulon, Naples, etc., each of these places becoming a new starting-point for the infection.
Countries spared by this scourge are exactly' those places out of snch com mercial roads, as are the islands of the north of Europe, Faroe, Hebrides, Ice land and Greenland, Baffin and Hudson Bays, Patagonia, western America, Poly nesia, Australia, central Africa, etc.
For several epidemics—those of 1852 and of 1859 in Europe afforded a striking example, for instance—a direct transmission of cholera from India could not be traced; so that they must be at tributed to a local revival of the cholera germ, with all its primitive attributes, in places where it had previously been carried from India. It seems, therefore,
that cholera germs of former •epidemics may live as saprophytes and wait until conditions arise, when they again become virulent.
The germs of cholera, when brought into some places, there to give rise to an epidemic of cholera, must find local con ditions favorable to their development.
Low, damp, marshy lands, large towns with crowded populations, narrow, dirty streets and generally every place in which the sanitary conditions are very imperfect and the inhabitants very poor are always the first and main centres of the disease.
Deeaying vegetable and animal mat ter, bad drainage, and overcrowding are as much responsible for cholera as bad drinking-water. The regular removal of fiecal matter and efficient surface- and subsoil- drainage will reduce the chance of introducing cholera into a town. to a minimum. Pal B. A. Mitra, (Indian Med. Pee., Feb. 15, '93).
Koch's vibrios traced to farm-yard ma nure, pigs' fxces being found to contain them. Nevertheless there had been no cholera for years in the region. Kutscher (Zeit. f. Hygiene u. Infectionskr., B. 19, p. 4G1. '93).
According to Pettenkofer, indeed, the most important part in the development of cholera is played by certain geolog,ical conditions of the soil (especially porosity and dampness), and by the variations in the level of the ground-water; so.that if such a soil become infected by choleraic germs, finding in it the best conditions for their growth, and, gaining there their virulent properties, the disease diminishes when the ground-water is high, and increases when its level sinks.
Investigations on 78 choleraic patients at the 116pital Beaujon. In 67 ca.ses the comma bacillus was- isolated. During, the epidemic the virulenee of the micro organism had diminished, for, in order to kill guinea-pig. a much larger dose of a culture isolated in September, 1892, was needed than of that Isolated in April of the same year. Girode (Comptes-rendus lfebd. des Sr..ances et Mem. de la Soc. de Oet., '92).