BOVINE TUBERCULOSIS. 



Bovine tuberculosis is one of the oldest diseases of animals of 

 which we have knowledge. It was known to the Egyptians in the 

 days of their captivity, and from then until now it has been a subject 

 of much thought and investigation. The opinions that have been 

 entertained concerning it have been changeable, the decrees of one 

 century as to its supposed infectious nature and the use of the flesh 

 of the infected animals often being reversed -by those of the following 

 century. History shows that up to the time of the introduction of 

 modern scientific methods for the study of disease, there was little 

 that was definite in our knowledge of tuberculosis beyond the fact 

 that it was a very destructive disease of both men and cattle. 



In 1865, tuberculosis was demonstrated to be infectious. In that 

 year Villemin showed that it could be produced in healthy animals 

 by inoculating them with pieces of tuberculous tissue. His results 

 were confirmed by a number of other investigators. In 1882, Robert 

 Koch discovered the bacillus* (or micro-organism) of tuberculosis 

 and thus completed the already abimdant evidence that tuberculosis 

 was a specific, infectious disease. The finding of its specific cause 

 led to many careful and extended investigations into the nature of 

 tuberculosis, the means by which it is spread, and the measures that 

 must be adopted if its spread is to be checked. The results of these 

 numerous inquiries have given us very definite knowledge of the nature 

 of the disease. It is believed that this knowledge, if properly used, 

 will enable every cattle owner to eliminate tuberculosis from his herd 

 if it is there, and to keep it out if it is not there. 



In order to have a clear understanding of what kind of a disease 

 tuberculosis is, it may be well to compare it with some disease that is 

 generally known and recognized to be infectious. For this we may 

 take diphtheria in children. It is well known that diphtheria is 

 caused by a micro-organism. This organism is known as Bacillus 

 diphtheria, or sometimes as the Klebs-Loeffler bacillus^ from its dis- 



*Bacteria (singular bacterium) is a general name for "germs" of a vegetable 

 or plant nature. A barilluf: (plural bacilli) is one kind of bacteria, distinguished 

 by being nuich longer than broad. A micrococcus is a spherical I)acterium. 

 General terms used to designate many of these minute forms of life are 

 "microbe" and "micro-organism." , 



