September, 1910 



AMERICAN HOMES AND GARDENS 



357 



A tuberculous bull. Dangerous in transmitting the disease to 

 other animals 



the matter? Surely Congress could not have closed its 

 purse had the condition as it was found to exist been laid 

 before it ! At any rate, Congress has now before it a bill 

 making provision for the amelioration of conditions as 

 they now exist over the entire country with regard to cattle 

 affected with tuberculosis. 



The scientists of the Department of Agriculture say that 

 tuberculosis or consumption, alike of persons and of cattle, 

 is an infectious disease, caused by the growth and multipli- 

 cation of a very minute plant in the bodies of its victims. 

 The little plant, which cannot be seen without the aid of a 

 microscope, makes up for its small size by the rapidity with 

 which it multiplies under favorable conditions. It is shaped 

 like a little rod and is known as the tubercle bacillus, and is 

 the one absolutely essential and indispensible cause of the 

 disease. Without it the disease does not and can not occur, 

 no matter how many conditions favorable to its develop- 

 ment are present. The greatest tuberculosis danger to 

 which animals are exposed, and likewise the greatest tuber- 

 culosis danger for public health that has its origin among 

 animals, is the tuberculous dairy cow, and dairy cows are 



A tuberculous cow of the kind not uncommon m dairy herds 



more commonly affected with the disease than other cattle 

 and other kinds of animals. This condition is supposed to 

 be due to the fact that dairy cows are more closely housed 

 than other animals. When milk is infected directly through 

 the udder it is exceedingly dangerous, because the tubercle 

 bacilli it contains are apt to be numerous and of the freshest 

 and most virulent kind. All cows affected with udder tuber- 

 culosis expel tubercle bacilli directly with their milk, and 

 some authorities believe that many cows, especially ad- 

 vanced cases of more or less generalized tuberculosis, also 

 do, though no tuberculous disease can be detected in their 



udders. Because of the long-concealed character of tuber- 

 culosis, through which it is especially dangerous when it af- 

 fects animals that are valued, like dairy cows, this concealed 

 character must be regarded as one of the important facts 

 about the disease; too many persons are inclined to take for 

 granted that a dairy herd is free from tuberculosis simply 

 because the cows of which it is made up look and act as 

 though in perfect health. And for that reason a study of 

 the accompanying illustrations will be interesting. Often 

 the disease progresses to nearly its fatal termination in 

 cattle without showing a well-defined symptom or an observ- 

 able sign of its presence. The only infallible way to dis- 

 cover whether an animal is affected with the disease is by 

 means of the tuberculin test. This test has been used in 

 thousands of cases by experts of the Department of Agricul- 

 ture and has always been found most reliable. Tests have 

 been made on cattle, hogs, horses, donkeys, goats, sheep, 

 and many other kinds of animals, and in some cases doses 

 of tuberculin from fifty to one hundred times as large as 



At the time this picture was taken this cow was a dangerous source for 



the spread of the disease. Without the tuberculin test she 



would have passed as a healthy cow 



those customarily used for a test have been injected, and 

 not one of the numerous tests was followed by an injury 

 to a healthy animal. 



The fact that any one organ or of several organs of a 

 cow may be almost wholly obliterated by tuberculosis before 

 externally observable symptoms of the disease assert them- 

 selves should be kept in mind by those who desire to free 

 their herds from tuberculosis, by those who desire to keep a 

 healthy herd free from the disease by avoiding the introduc- 

 tion of tuberculous cows into it, and by those who wish to 

 protect themselves from that exposure to tuberculosis which 

 comes to persons through the use of milk and other dairv 

 products coming from animals affected with the disease. 



A cow m a well-nourished condition with advanced tuberculosis 



