MICROBIAL DISEASES OF MAN AND ANIMALS. 607 



seem susceptible. The disease produced is usually fatal. Usually 

 the most conspicuous general symptom is unthrift in spite of good 

 appetite and good food. 



This microorganism is a rod-shaped bacterium from 2^ to 3/1 long 

 and about O.^/JL broad and is strongly acid-fast. The production of 

 active toxins is to be presumed since the amount of disturbance is fre- 

 quently out of all proportion to the lesions found on examination post 

 mortem. 



The bacteria are present [in the faeces, intestinal mucosa, and sub- 

 mucosa, most frequently of the small intestines. The large intestines 

 may be involved later. 



This microorganism produces chronic, inflammatory changes of the 

 intestinal mucous membrane, the whole intestinal wall becoming greatly 

 thickened. 



This bacterium resembles closely avian tubercle bacteria, but may be 

 distinguished by the fact that the avian tubercle bacterium is rather easily 

 grown on artificial media. This organism does not have the same 

 pathogenic peculiarities as the avian tubercle bacterium. It seems well 

 demonstrated that cases of chronic bacterial enteritis do not react to avian 

 tuberculin; but this does not exclude identity. 



So far as known the bacterium is eliminated in the manure of 

 affected cattle and disseminated in this way. Wider dissemination is 

 made by diseased animals moving from place to place. 



The most important considerations in controlling this disease are 

 careful disposition of contaminated manure and isolation of suspected 

 animals. The manure should be used only where it can not serve to 

 spread disease to other cattle. Sick animals should be carefully isolated 

 and premises thoroughly disinfected. 



CONTAGIOUS ABORTION OF DOMESTIC ANIMALS.* 

 Bacterium abortus. 



The premature discharge of the products of conception from the 

 uterus is a not infrequent occurrence among domestic animals, and doubt- 

 less various factors may from time to time operate in its causation. 

 Injury, excessive fermentable food, or poisonous food may at times 

 produce this result. For a long time, however, practical husbandmen 



* Prepared by W. J. MacNeal. 



