84 



Journal of Agrictdture, Victoria. [lo Feb., 1912. 



The anthrax bacillus is quickly destroyed in the presence of putre- 

 faction and septic ferments, and as decomposition of an unopened anthrax 

 carcase is very rapid the search for the bacilli may be fruitless if the 

 examination is delayed till putrefaction is advanced. Not only may the 

 bacilli not be found by microscopic examination, but the blood and tissues 

 will not be infecti\"e to other animals after a few days except in those 

 cases where, through admission of air, the bacilli have sporulated. In 

 such cases the bacilli would have become disintegrated but the spores 

 would produce anthrax in any susceptible animal inoculated. This fact 

 has an important bearing on the diagnosis of the disease and also upon 

 the suppression of its spread. It will be obvious that microscopical and 

 bacteriological methods of diagnosis cannot be relied on except when the 

 examination is conducted on comparatively fresh specimens, taken in a 

 manner to minimize risk of contamination with putrefactive organisms. 

 Even as regards inoculation, Friedberger and Frohner set out that " in- 

 oculation gives negative results when the matter containing the bacilli is 

 soiled by other microbes or is in a state of putrefaction." 



On the second point, as to pre- 

 venting the spread of the disease, 

 seeing that spore formation in the 

 bacilli does not occur in the living 

 animal nor in the carcase to any 

 extent if air and oxygen are ex- 

 cluded and that the bacilli them- 

 selves are quickly destro^-ed after 

 the death of the animal, it follows- 

 that the risk of spread of the dis- 

 ease is greatly lessened if the car- 

 case is not cut or opened up to con- 

 tact with air. The germs are im- 

 prisoned, so to speak, and die 

 from oxygen starvation. Any risk 

 there is lies in the possibility of 

 the discharges from the carcase 

 containing bacilli which, on contact 

 with the air, form spores by which the contagion may be propagated. If,. 

 however, such discharges are collected and burnt along with the carcase,, 

 or buried deeply with it, the risk of spread of anthrax may be reduced to a . 

 minimum. It is this quick destruction of the bacillus by decomposition 

 and the absence of sporulation that accounts for that sudden cessation of an 

 anthrax outbreak which is so frequently observed and which appears so. 

 inconsistent with the expected behaviour of a contagious disease. 



When the bacillus has become liberated from the carcase it may be 

 preserved in the soil and propagate for an almost indefinite length of 

 time. This is more likely to occur if the soil is rich in organic matter, 

 and hence moist alluvial lands are notoriously more retentive of anthrax 

 infection than dry uplands. A paddock with anthrax-infected soil rnay 

 not produce anthrax for years, until the occurrence of conditions which 

 favour the transmission of the germs from the soil to the herbage. In 

 very damp seasons the germs may be brought to the surface by the eleva- 

 tion of the water level on swampy ground ; or they may be washed out by 

 floods and deposited on the surface ; or the excessive moisture may bring 

 up earth worms whose earth casts may contain bacilli from an anthrax- 



A. Anthrax bacilli in blood. 



B. Filamentous development of anthrax 



bacilli on artiticial culture. 



