CHAPTEE XXI. 

 CONTAGIOUS DISEASES AND THEIR SUPPRESSION. 



Diseases of germ origin have become of great import- 

 ance to the stock raiser in recent years and are more 

 easily controlled than formerly, owing to the work of 

 bacteriologists and veterinarians. Hygiene, which 

 means pure food, good water, pure air, sunshine and 

 cleanliness, prevent the harboring of germs and thus limit 

 or prevent their propagation. 



Tuberculosis, commonly termed consumption, is quite 

 prevalent in the human race and in cattle is not 

 at all uncommon. The cause of the disease is the 

 bacillus tuberculosis, discovered by Koch in 1882. 

 Heredity is only a predisposing cause, as are lack 

 of pure air, innutritious food, lack of sunlight, as 

 in dark basement barns, etc. The disease is not easily 

 discovered in the early stages without the aid of the 

 tuberculin test, which is a very reliable method when 

 when in the hands of competent men, and is entirely 

 without danger to the animal tested; in the latter stages 

 of this serious trouble the disease is evidenced by a fre- 

 quent cough, general ill-health, shown by the staring 

 coat, capricious appetite, and sometimes a stinking diar- 

 rhoea. Treatment in the usual sense of the term is not 

 practicable; but the progress of the disease in a herd 

 may be arrested by culling out the diseased cattle at least 

 once a year by means of the tuberculin test, separating 



