Bovine Tuberculosis in Its Kelation to IIan. 129 



bovine species, the two great families in both of which it exists 

 to an alarming extent. The disease occurs in a limited way in 

 several of the domestic animals other than the ox, but assumes 

 very little practical importance so far as they are concerned. 

 The disease is a slow and insidious one, wholly different in this 

 respect from such diseases as cholera and small-pox of the human, 

 or cattle plague of the bovine. Tuberculosis in cattle does not 

 necessarily kill; on the contrary, many animals maintain ordinary 

 health and high condition, apparently suffer no inconvenience 

 from it, and finally die of some other cause. In other instances 

 there are signs of constitutional disorder with more or less of 

 the symptoms common to it, and in acute cases followed by death 

 within a few weeks or months. 



Breed. — All breeds are susceptible. It has been erroneously 

 believed that Jersey cattle were most prone to tuberculosis, but 

 the royally bred and the common scrub are alike subject to it, 

 just as the various races of men are. 



Sanitation and Spontaneity. — The old writers gave as some of 

 the causes of tuberculosis, bad ventilation, filth and insanitary 

 conditions generally. No combination of ill conditions can pro- 

 duce a single case of the disease, nor can the most perfect and 

 elegant buildings and hygienic surroundings offer immunity from 

 it. Of course this is easily accounted for now that the means of 

 infections are understood. 



Heredity. — Dobson, quite an authority a few years ago, in his 

 work on the ox, says: "There seems to be no doubt as to the 

 hereditary character of this affection, so that in no case should 

 a bull be chosen from stock which are thus diseased. ... A 

 report to the parliament of Victoria, New South Wales, in 188G, 

 says that heredity certainly plays a most important part in the 

 propagation of the disease." This is the opinion of about all 

 veterinary writers. Since the discovery of the tubercle bacillus 

 and the application of the tuberculin test, it has been found that 

 calves from tuberculous dams, if removed immediately after birth 



