Specific Contagwus Diseases. 113 



gangrene, yellow or browu mucous membranes, enlarge- 

 ment or even rupture of the spleen (milt), and a very high 

 mortality. The germ is a bacillus viable out of the body 

 in damp soils, etc. 



Causes. It is propagated by contagion but tends to die 

 out when produced in this vray only. It is transmitted by 

 contact with the blood, liquid exudations, portions of the 

 diseased carcase, fat, skins, hair, wool, bristles, feathers, and 

 bowel evacuations, and rarely or not at all through the at- 

 raosphere. Simple contact of these matters with the healthy 

 skin of a susceptible subject is at times enough to produce 

 the disease. The virus is most potent when received fi-om 

 an animal still living or only recently dead, and yet may be 

 preserved for months in all conditions of climate, tempera- 

 ture, and humidity. 



Eating of the flesh of animals killed while suffering in 

 this way has often conveyed the disease despite the cooking 

 to which it was subjected. Fifteen thousand of the inhab- 

 itants of St. Domingo once perished in six weeks from this 

 cause, and a whole family M^as poisoned a few years ago in 

 Aberdeenshire, Scotland. The Tartars perish in great num- 

 bers from eating their anthrax horses. Mosquitoes and other 

 insects with perforating apparatus to the mouth help to com- 

 municate it, as nearly all cases in man occur on exposed parts 

 of the body, and inoculation of the insects' stomachs has 

 caused the disease. 



Its preservation in a locality is determined : 1. By the 

 rich surface soil abounding in organic matter, and the im- 

 pervious subsoil preventing natural drainage. 2. The fre- 

 quent inundations of banks of rivers flowing through level 

 countries and the drying up of ponds and lakes leaving mucli 

 organic deposit in their basins. 3. A continuation of warm, 

 dry weather, which favors organic emanations from such 

 places as the above. 4. A condition of the system of the ani- 

 mal predisposing to the i-eception and growth of the poisoHj^ 



