110 IOWA DEPARTMENT OF AGRICULTURE 
of 25 per cent of the cases are due to the cattle germ. In Washington the 
other day Dr. made the statement in Koch's presence that of 
the cases of tuberculosis of the glands of the neck one-half are due to the 
cattle germ. 
Some of you will say: "Koch is the man that discovered the tubercle 
bacillus, and he ought to be listened to." I agree with you; but is he the 
only rhan? In spite of his discovery he worked twelve years without 
finding any difference between the human and bovine germs, and he worked 
nineteen years without finding out that the cattle germ could be trans- 
mitted to mankind; and he was not the man who taught us the best 
method of growing the germ which is used in Germany to-day. Who are 
the men who hold contra views to him? The w^hole scientific world. He 
has not one single backer that I know of. Do not understand me as trying 
to belittle Professor Koch's great work and discoveries, but I think it is 
a mistake to say that he is the only man entitled to any opinion on this 
subject. 
I have in my pocket at this moment a record of a family of nine people 
of whom eight died with tuberculosis, with no family history whatever. 
The only member of the family who escaped did not drink milk, all the 
others being great milk drinkers. In another family in the same block 
four died of tuberculosis, drinking the same milk. I don't give you that 
as absolute proof, because the germ was not isolated and proved to be 
bovine. But it won't be long, I believe, before no farmer can sell any 
dairy product in any city of the United States unless he can show that it 
comes from clean herds, and I don't think I can give you any stronger 
argument for getting clean herds and keeping them clean than I have 
given. 
Question : Wliat is the best way to disinfect stables ? 
Dr. Ravenel: Light will kill every germ known. Direct light 
kills them in from one minute to one hour, but even diffused light 
will clean out any stable in 36 to 48 hours. I would say, have light, 
clean stables, with plenty of fresh air. Use a strongly alkaline soap 
and thoroughly scour. The best disinfectant for general use is 
what we call milk of lime. Get lime and water-slack it — about 60 
parts of water to 100 of lime; and then take one part of that to 
four parts of water. If you have any rotten wood, clean it out and 
put in fresh bedding. Put in cement floors if you can. Leave your 
stable vacant for eight or ten days. Formaldehyde is the best dis- 
infectant, but it is not possible to use it in the average stables very 
efficiently. 
The next on the program was an address by Dr. P. 0. Koto, 
State Veterinarian, on "Bovine Tuberculosis." The subject matter 
of this address will be found in full in part IX, Extracts from State 
Veterinarian's Report. 
