230 IOWA departme>:t of agriculture. 



have tuberculosis in your cattle you will have it in your hogs. You can 

 test it by tuberculin test. There is a chance for a mistake, but the per- 

 centage of mistakes is very small, so that for all practical purposes it is 

 the best one we have. It is not infallible, but it is a good test. In this 

 infection of tuberculosis we find that there are practically three kinds, 

 pulmonary, intestinal and mammary; pulmonary, of the lungs; intestinal, 

 of the intestines; and mammary, of the mammary glancis. We know that 

 in cattle the infection is brought by the air or the food. It can be car- 

 ried, and we know that infection is by the animal having tuberculosis of 

 the lungs and expectorating this matter, but instead of spitting it out they 

 swallow it and it passes through the digestive tract, and by this method 

 you get an intestinal infection. You might have the lung infection; sec- 

 ond, the abdominal or intestinal infection, and lastly the mammary infec- 

 tion. You do not have to have tuberculosis of the mammary glands in 

 order to get tubercular germs in the milk. This is one of the most pro- 

 lific sources of its being transmitted to calves and pigs. Y'ou can have 

 what we call generalized tuberculosis or local tuberculosis. Local tuber- 

 culosis does not enter the blood serum, but as soon as it enters the blood 

 serum it is generalized; from the heart to the lungs and the different 

 organs of the body, in the spleen, heart, and so on. Tuberculosis is not 

 what we call blood poisoning, meaning a condition in which we have 

 septic material in the blood not longer than six days after inoculation. 

 Tuberculosis, first, last and all the time, unless it becomes generalized, is 

 local. The kernels that come in the neck are distinctive. You find that 

 they enlarge. You get them in the armpit, in the limphatic gland, and as 

 the gland becomes broken down, like the outpost of the army, the enemy 

 advances and marches on and on until they are in the fort. So the infec- 

 tion follows from one gland to another until it becomes generalized. From 

 that you get mammary tuberculosis. During the time the tubular germs 

 are circulated in the blood they may be excreted through the cells into 

 the milk and then fed to hogs and calves or to human beings. Of course 

 they do not always react or become affected. In this mammary form of 

 tuberculosis there are some symptoms by which you can tell between 

 mammary tuberculosis and what you know as garget. In the one the 

 swelling may take place in one quarter or in several quarters, but usually 

 only in one quarter. The swelling is very hard, painless and without heat. 

 In garget you usually find the swelling painful, very hard and rapid in its 

 formation. The one is chronic and the other is not. In using animals for 

 dairy purposes you should exclude the individuals that have anything 

 wrong with the mammary glands from milking and have them shipped or 

 sent to the butcher or something done besides using them for dairy pur- 

 poses. Now as to the amount of this mammary tuberculosis. In the tests 

 that have been made, and especially in Germany, where they have a rigid 

 inspection and where they carry it on in a good manner, they find the 

 number of animals that react about 6 per cent; in this country 2 per cent, 

 so that two cows out of a hundred have mammary tuberculosis. Suppose 

 you have a dairy where there are probably three hundred cows. You 

 would have in the three hundred, six cows that are discharging bacilli in 

 the milk at every milking. What do you do with it? Send it to the cream- 



