Anthrax. 199 



sive manuring, tend to preserve and multiply the microbe. Rich, 

 flat meadows below tanneries or abattoirs, and irrigated from 

 these or occasionally overflowed are especially dangerous to stock 

 placed upon them. Soils with an alkaline reaction from the lime, 

 potash or ammonia present are very favorable to anthrax. Wells 

 receiving surface drainage are common factors in carrying infec- 

 tion. 



Season is a contributing factor in various ways. Damp seasons 

 sometimes bring the germ to the surface of the soil by the 

 gradual elevation of the water level, or by causing inundations 

 and the deposition of the bacillus on areas of pasture or forage 

 that were previously free, or finally by bringing the earth-worms 

 to the surface and leading to the deposition in their casts of the 

 bacillus brought from the infected graves or retentive subsoils. 

 Dry seasons are, however, the anthrax seasons par excellence, as 

 they dry up swamps, fens, ponds, lakes, basins, deltas and bot- 

 tom lands, and render them available for pasture. The germ- 

 laden mud of these drying lands is also raised in dust and de- 

 posited on the vegetation to be taken in by the animals. Again 

 on the drying basins and bottom lands the tempting green vege- 

 tation is often pulled up by the roots with adherent, infecting 

 mud. For the above reasons, even in an anthrax region the malady 

 is most prevalent in the late summer and fall, and in certain 

 valleys like those of Corsica the stock is considered safe until the 

 dry autumn weather demands their removal to the mountains. 



Another reason for the summer epizootics is found in the trans- 

 ference of the germ by flies. House flies, horse-flies, blow- 

 flies, mosquitoes, etc., carry the bacillus on their feet, mandibles 

 or piercing apparatus, and even in their stomachs (Bollinger) and 

 transfer it from one individual to another. It is worthy of note 

 that the great majority of cases of local anthrax in man occur on 

 the habitually uncovered parts of the body (face, neck, hands 

 and arms) and start from a centre like the bite of an insect. 



Stables, stable utensils, harness, shafts, poles, fodder and litter 

 are familiar bearers of the virus. Butchers' knives and wagons 

 and surgical instruments are further media of contagion. 



Certain conditions of the animal system expose it to attack. 

 The fever and constitutional disturbance which are caused by 

 the extreme heats of summer and autumn are strongly predisposing, 



