254 THE DISEASES AND DISOEDERS OF THE OX. 



as a rule they die in the course of about two or three days from 

 its commencement. 



There is an effusion of fluid into the tissues beneath the 

 skin and in those which lie between the muscles of one or more 

 of the legs, or between those of one hind limb and one fore- limb. 

 As a consequence of this swelling, or of these swellings, the 

 animal moves with pain and difficulty. The swellings which are 

 thus formed contain many bacilli, and these small, rod-like 

 vegetal organisms are likewise present in the internal organs. 

 According to Dr. Klein, they are about the size of, but a little 

 thicker than, the bacilli of anthrax fever. Their ends are 

 rounded, and at one of the ends a bright oval spore is often 

 enclosed, which is not the case in regard to the bacilli of 



^O 



Fig. 32. 



Blood of a Guinea-Pig dead op Symptomatic Anthrax (Black-leg). 



Blood corpuscles, and between them several bacilli. Magnifying power, 700. 

 (Klein.) 



anthrax fever. These bacilli of black quarter are either single 

 or form short chains, and some of them move about. If a fluid 

 containing these bacilli be injected under the skin of calves, or 

 sheep, or guinea-pigs, or rabbits, the same disease, black- 

 quarter, is thereby occasioned. If only a very small amount of 

 the fluid containing the bacilli be injected into the veins, only a 

 slight fever is produced, whereas larger quantities cause death. 



Animals, however, which have suff'ered slight disorder owing 

 to injection of small quantities of the virus either into the veins 

 or under the skin, are afterwards protected against what would 

 otherwise prove a fatal dose. In other words, if the malady is 

 produced artificially in a mild form, the animal is thereby 

 ensured against death as a result of this particular disease. 



Black leg is a very fatal and infectious disease. 



