366 IOWA DEPARTMENT OF AGRICULTURE 
When tested with tuberculin twenty out of the twenty-four reacted to 
the test, and these were taken to the packing house at Cedar Rapids, 
where they were slaughtered. The post mortem gave evidence of tuber- 
cular lesions in each of the animals slaughtered, and we reproduce here 
a photograph of one of the animals after it had been subjected to post 
mortem. The tubercular lesions are present in such pronounced form 
as to indicate the wisdom of the test and subsequent slaughter of all 
diseased animals. Many other herds in the same locality were tested, 
and those reacting were disposed of in a similar manner. 
The progress of Bovine Tuberculosis is ordinarily very slow, often 
taking years to destroy its victims. The period of incubation is inde- 
finite, varying from a few days to months; but the germ once entering 
into the system of the patient, unless very robust, passes through the 
circulation and starts its destruction. It often happens that the organism 
passes into other parts of the body, thus producing the condition known 
as Generalized Tuberculosis, then two or more organs may be affected; 
such as the lungs in the plural cavity and the liver in the abdominal 
cavity. An animal in this condition of tuberculosis of a closed cavity 
like the plurse may not be a source of infection to a herd for years, yet, 
from the migration of the germ of tuberculosis passing to other organs, 
especially the bowels, might become a prolific source of infection. 
The chief industry of our state consists of live stock, and in attempt- 
ing to eradicate tuberculosis we must pursue a course that will be of 
greatest benefit to all. The interests of the farmers, breeders and stock 
raisers, consumers of vast dairy products must all be considered. It is 
a difficult matter to determine to what an extent it exists among live 
stock in the State of Iowa, but it is safe to predict that the losses from 
this disease, directly and indirectly, amounts to millions of dollars. The 
financial losses being so great makes the eradication of tuberculosis from 
our live stock necessary, and the movement must be carried out as a 
matter of economy and as a protection to the public health. 
According to the Iowa Year Book of Agriculture the number of milch 
cows in Iowa January 1, 1908, was 1,429,017, at an average price of 
$33, equals $47,157,561; stock cattle, 3,548,493, at an average price of 
$25, equals $78,712,325, making a total value of milch cows and stock 
cattle $125,869,886. 
According to the estimate made by Dr. A. D. Melvin, Chief of the 
Bureau of Animal Industry, the average loss from tuberculosis among 
milch cows will be 9^4 per cent, making a total value of $4,362,074; and 
the loss among stock cattle about 1 per cent, amounting to $787,123, 
making a total value of $5,149,197. The number of swine in Iowa is 8,366,- 
520, at an average of $9 apiece, would make a total value of $75,295,680; 
and the loss among swine due to tuberculosis is estimated by the same au- 
thor at 2 per cent, making a value of $1,505,973, making a total value of 
cattle and swine affected with tuberculosis in the state of Iowa $6,655,170 
annually. Thus the loss from tuberculosis among live stock would practi- 
cally amount to more than the loss from all other diseases combined; 
and it is estimated that one death in seven, of all the deaths in the 
