12 Veterinary Medicine. 



Morphology . This is a staff-shaped microbe 3-4 /a. long by 1 /x. 

 broad, often united in chains of three or more to form long flexu- 

 ous filaments. They are furnished with numerous flagella by 

 which they are rendered very actively motile. The movements 

 are tardy or simply flexous in the filaments. Spores form in the 

 isolated bacilli (not in the filaments) in suitable culture media and 

 at a temperature of from 20 to 38 C. They occupy a place near 

 the centre of the bacilli, not the ends as in the bacillus of emphy- 

 sematous anthrax. The bacilli are anaerobic and die quickly in 

 air, but the spores are unaffected by oxygen. The spores are simi- 

 larly resistant to most disinfectants. They will grow readily in 

 ordinary culture media if oxygen is excluded, for example under an 

 atmosphere of hydrogen, nitrogen or carbon dioxide, and liquefy 

 gelatine. Even the oxygen present in the circulating blood is 

 highly inimical to them, so that they are rarely found in the blood 

 during life, but rapidly invade both it and the tissues after death, 

 and the suspension of respiration. In peptonised and glucosed 

 gelatine the colonies are characterized as globules of liquefaction 

 usually combined with gas. The germ is widely distributed in 

 soils in general and not confined to limited areas like the bacilli of 

 anthrax and black quarter. 



Animals susceptible. The bacillus attacks man, horse, ass, 

 goat, sheep, pig, mouse, Guinea pig, rabbit, white rat, cat, dog, 

 chicken, pigeon, and duck. The mature ox is immune, but 

 calves suffer. Dogs are often immune having already suffered 

 from the disease. A first attack gives immunity from a second. 



Infection Channels. Inoculation on an abrasion of the skin or 

 surface sore is not usually infecting, the oxygen of the air des- 

 troying the germ. If, however, it is inserted deeply in the con- 

 nective tissue, subcutem, it grows readily in a susceptible animal. 

 Hence the danger of infection in deep wounds the recesses of 

 which are not exposed to the air, and in such it becomes a most 

 redoubtable surgical complication. If such wounds are the seat 

 of active inflammation, with abundant exudate and more or less 

 exclusion of the air-bearing blood, and in cases of blood stasis 

 the field is specially inviting to the bacillus. 



The debility of the injured tissue is a further invitation to the 

 attack. Chauveau injected 4 to 5 cc. of virulent liquid of malig- 

 nant oedema into the veins of a ram and then practised bis- 



