ANTHRAX. 287 



as asphyxiants, depriving the blood of its oxygen ; and (2.) By 

 mechanically obstructing the blood-vessels. Against both these 

 theories must be placed the fact that they are very few in 

 number, indeed often absent altogether in the blood during life. 



Anthrax is not transmitted by infection from one animal to 

 another, for animals kept in the closest proximity to diseased 

 ones, and placed under the most favourable conditions for infec- 

 tion through the air, do not become diseased. 



Mice and rabbits seem capable of eating food containing 

 bacilli with impunity, and flies can gorge themselves with the 

 infected blood and suffer no harm ; but horses, cattle, pigs, dogs, 

 cats, and ferrets succumb after partaking of food and water 

 contaminated with the virus. 



It is now generally admitted that animals are infected by 

 spores contained in the food, which gain entrance into the circu- 

 lation either through abrasions in the mucous membranes of the 

 digestive track, or, as some assert, by the pulmonary mucous 

 membrane ; but this is doubtful. My own experience leads me 

 to conclude that undecorticated cotton cake is the most fertile 

 source of the disease of all the artificial foods, and it seems to 

 acquire virulence after being kept for some time, particularly if 

 neglected and allowed to become heated and mouldy. When 

 freshly made, it seems to have no effect, and I have known 

 several instances where cattle have eaten the same cake for 

 weeks or even months before becoming affected, then all at 

 once they have died off. I am of opinion that the spores — few 

 in number — have been present in the cake from the first, and 

 that they multiplied in the cake, which, as is well known, is 

 imperfectly dried ; thus, after repeated reproductions of the 

 organisms, the cake has become sufficiently charged to induce 

 the disease in its partakers. The decorticated cotton cake is 

 differently prepared, being highly dried and submitted to great 

 pressure ; thus heating and fermentation are prevented, and any 

 increase of the organisms rendered impossible. 



When soil is contaminated with the blood or discharges of 

 animals dead of anthrax, it is found that spore formation goes 

 on actively in many moist and warm media, and it is stated that 

 these spores may be conveyed by floods to surrounding pastures. 

 It is also supposed that the organism may grow as a saprophyte 



