198 INFECTIVE DISEASES. 



Origin and Mode of Speead. 



As every outbreak of anthrax is the result of the introduction 

 into the system of the bacilli, the question naturally arises, how- 

 are they introduced on the farm ? Where do they come from ? and 

 what are the channels of infection ? 



The spores of the bacilli may get into the soil, and may remain 

 there in a dormant state for many years. The spores were believed 

 by Pasteur to be taken up by earth-worms, carried to the surface 

 and deposited in their castings. Animals grazing are thus liable 

 to be infected ; but Koch's experiments tended to disprove this 

 theory. Anthrax has been known to break out among cattle 

 grazing on a field where several years previously some Russian 

 hides from infected animals had been buried. By some means or 

 other the spores may contaminate the grass, and hay imported 

 from an anthrax district may start the disease on a farm on which 

 it had never been known to occur. The spores may in a similar 

 way be introduced with blood manure and bone manure, and with 

 refuse used as manure. The skin, hair, wool, hoofs, and horns of 

 infected animals, if soiled with blood, are contaminated by the 

 bacUlus. 



Another way in which the disease can be communicated may 

 be illustrated by the transmission of the disease to man. Those 

 who handle carcasses, wool or hides of infected animals are liable to 

 contract the disease. Slight scratches, cuts, bites, and pimples, may 

 readily be inoculated with the bacilli or their spores. Veterinary 

 surgeons, butchers, herdsmen, cattle drovers — in fact, all those whose 

 occupation leads them to cut open or skin cattle, sheep, or horses, or 

 to handle hides and wool — are liable to fall victims to this disease. 



In one case which was brought to the author's notice, a veteri- 

 nary surgeon had been called to see a bullock which had died 

 suddenly in a meadow. A post-mortem examination was made, and 

 the veterinary surgeon wiped his hands, which were soiled with 

 blood, on some rough grass, and then washed them in a stream. 

 The sedgy grass made some small cuts on his fingers, and the 

 result was that he was simultaneously inoculated with the blood 

 of the bullock. Local anthrax followed, two of his fingers were 

 amputated, and he fortunately recovered. In another case a butcher 

 dressed the carcass of a beast which had died suddenly, and while 

 doing so scratched a pimple on his neck. An anthrax pustule 

 developed, and after a very serious illness he also recovered ; but 

 in many cases the attack is ' fatal. " Wool-sorters' disease " is 



