TRANSMISSION OF BOVINE TUBERCULOSIS. 207 



virus is evident, and that even the flesh of such diseased animals 

 under certain circumstances, and also the milk, possesses infective 

 properties, though to a less degree than the cheesy matter from the 

 lungs. 



That tuberculosis is now rapidly on the increase no well-informed 

 veterinarian can deny. It ranks among the few great scourges of 

 the land ; and though our losses, thus far, in live stock propert}^ 

 have been largel}' due to other plagues which sweep their victims off 

 in a summary manner, yet the ravages of this disease can only be 

 realized, says Prof. Walley,* when we take into account the vast de- 

 terioration, the slow but certain decimation of man}' of our best 

 herds, the destruction of our animal supplies, and also the danger 

 to human life which can no lonsrer be considered chimerical. Still 

 there are many who from want of knowledge on the subject may even 

 despise the pathological significance of this fell destro3'er and thus 

 ignore its deadly meaning ; but when we see thousands of these 

 tubercular deposits in a single slaughtered animal, we are forced to 

 conclude that the use of such meat can in no wa}' promote our health- 

 fulness. Thus we have in every form of tubercle an implacable and 

 destructive foe, and, in fact, there is no other morbid product known 

 that is so protean in the number of functional derangements to which 

 it may give rise in the animal economy. 



HEREDITARY TRANSMISSION. 



There is evidently a strong pre-disposition in neat stock for the 

 production of tuberculosis, and cattle are far more frequently affected 

 than other domestic animals. The temperament and physical con- 

 formation undoubtedly contribute much to its development ; for ani- 

 mals of a phlegmatic type, with an attenuated form, long limbs, and 

 narrow chests, are usually the first victims of the malady. Breeders 

 should therefore strive to avoid the possibility of transmitting such 

 diseased qualities. It is more frequent in cows than in oxen, and 

 especially those kept in dairies for a length of time. Hence lac- 

 tation is believed to be a predisposing cause. The condition also in 

 which animals are kept is no small factor. The cold, damp sheds, 

 the dark, underground stables, and other ill-ventilated abodes, as 

 well as the character of the food, all conspire to rekindle those con- 

 stitutional taints into morbid activity. 



*0p. Cit., page 143. 



