microbial diseases of man and domestic animals 785 



Malignant (Edema* 

 Bacillus cedematis maligni 



The disease occurs as the result of infection of wounds with dust or 

 soil. The wounds must involve the tissues deeply as in compound 

 fractures and deep cuts. „ 



Any animal may be infected, although the dog and cat are said to be 

 rather more resistant than others. 



The incubation period is short, from one to two days as a rule. 



The usual case begins with sudden spreading haemorrhagic sub- 

 stances, oedema and high fever. Practically no gas is formed. The 

 fluid shows bacilli both with and without spores. Where soil contami- 

 nation exists, mixed infections with gangrene are common. 



Pasteur in 1877 and Koch and Gaffky in 1881 found and studied 

 the organism and by passing from animal to animal established the 

 causal relationship. 



Glucose agar or glucose gelatin is inoculated with the suspected fluid, plates 

 pouied and placed under anaerobic conditions. The organism is o.S/t to i/i wide. 

 Filam^ts may occur. The rods without spores are uniform in width with slightly 

 squared ends. They are usually single, though pairs end to end are frequent and 

 chains are also found. Oval spores are formed somewhat variable in their position, 

 with a diameter usually larger than that of the vegetative rod, bringing about a 

 spindle shape. Peritrichic flagella have been demonstrated, about twenty in 

 number. It stains readily with aniline dyes, usually Gram-negative though some- 

 what variable and indefinite in this regard. Growth takes place at both 20° and 

 37°. It is a strict anaerobe. Like anaerobes in general it prefers the presence of a 

 fermentable carbohydrate such as glucose. On agar the colonies are small, whitish, 

 ' and irregular in outline. Gelatin and blood serum are digested, caseinogen is 

 changed to casein which is then digested. In both protein and carbohydrate media 

 a gas is produced which has a very disagreeable odor. The spores are very resistant. 



This resistance accounts for its continuous presence in earth and 

 dust and as a constant inhabitant of the intestine of animals, especially 

 of herbivora. 



MiLKSICKNESst 



Bacillus lacti morhi 



Milksickness, a disease so called because of it being most commonly 

 transmitted to man through milk of infected cows, is caused by the 



* Prepared by Edward Pidlar. 

 t Prepared by Norman Mac L. Harris. 

 50 



