Anthrax. 



197 



of domestic animals and thousands of human beings to suffer in 

 a single year. 



The geographical distribution of the disease is largely influ- 

 enced by soil and climate. On dense, impermeable clays and 

 hardpan subsoils, on river bottom lands, dried lake basins and 

 deltas, rich in organic matter, and with the. air driven out by 

 water or gaseous fermentation products, the germ is preserved 

 and propagated if once introduced. Thus it is common around 

 the mouth of the Nile, and along the occasionally inundated 

 banks of the Vistula and Danube, the Spree, Oder, Elbe, Rhine, 

 Eure, Loire, Seine and Marne, and in England in the Fen dis- 

 trict. On the rich, undrained, black soils of Siberia it is ex- 

 tremely prevalent and fatal. In the rich Genesee Valley, N. Y., 

 the writer has seen 200 cattle in one herd and three human at- 

 tendants attacked in the course of a fortnight, and in different 

 meadows receiving the drainage of tanneries, the affection pre- 

 vails every summer and autumn. It is much more prevalent in 

 the rich lands of the Southern States and a widespread and deadly 

 epizootic prevailed in Louisiana in 1896. Where the soil is 

 favorable, the germ may be preserved indefinitely, even in moun- 

 tainous districts, and near Los Angeles, Cal., where the disease 

 was introduced in imported sheep some years ago it has become 

 permanently domiciled, on the dry ranges which have moist 

 lands (Cienegas). When an outbreak occurs, the herds or flocks 

 are usually moved to higher soil, and the carcasses being left uu- 

 burned and unburied the infection is spreading year by year 

 (McGowau, Morrison). 



Etiology. Nothing is more certain than that the disease is due 

 to the introduction into the blood or tissues of the bacillus anthra- 

 cis or its spores. These microbes are always found in the anthrax 

 lesions and in the blood of the victim in the advanced stages. 

 When grown in bouillon cultures to the hundredth generation 

 they retain their virulence unabridged and determine the same 

 lesions in the animals inoculated. When the infecting culture 

 has been passed through a Pasteur filter the virulence is lost with 

 the removal of the bacilli. The fresh anthrax blood containing 

 bacilli but no spores when subjected to compressed oxygen (50 

 atmospheres) becomes non-infecting. The same liquid when 

 boiled proves non-virulent. 



