CHAPTER 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 cleanli- 

 ness, 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 tu- 

 berculosis, discovered by Koch in 1882. Heredity is only 

 a predisposing cause, as are lack of pure air, innutritions 

 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 in the hands of competent men, 

 and is entirely without danger to the animal tested; in 

 the later stages of this serious trouble the disease is evi- 

 denced by a frequent cough, general ill-health, shown by 

 the staring coat, capricious appetite, and sometimes a 

 stinking diarrhosa. 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 the healthy from the unhealthy, and 



