DAIRY MEETING. 8l 



food, warmth and moisture, and where they lodge they may 

 grow, and the one organism that entered and contaminated the 

 animal may in a few days be millions of organisms. 



The food contaminated with the germs may be eaten, and 

 some slightly abraded surface of the mucous membrane may 

 serve as a favorable place for their growth. Now what takes 

 place? At first they cause a little local irritation. It is just as 

 though the part had been injured by a blow. There is a little 

 inflammation there, a little increased blood supply, and the organ- 

 isms as they grow throw out a poison that acts first locally, and 

 we have an inflamed surface that is not easily discovered, less 

 in area, perhaps, than the size of a pin-head. At that stage of 

 the disease it would take a microscope to determine definitely 

 that the animal had any disease. That condition may continue 

 for a considerable length of time, for we find that these organ- 

 isms do not grow without some opposition, in the living animals. 

 It is sort of nip and tuck between the animal life and the plant 

 life. The animal does not surrender at discretion. If he is in 

 vigorous physical condition, the germs may just barely live and 

 for a long time hardly get beyond that. So we have animals 

 aflFected with tuberculosis for years, and but little diseased tissue 

 showing. But the day comes when they catch the animal in a 

 weakened condition. Conditions are more favorable for the 

 growth of the organism. This little diseased area then enlarges 

 more rapidly, and it chances that some of the organisms that 

 are growing here find their way into a lymphatic vessel or into 

 a blood vessel and are carried on to some neighboring part of 

 the body, and where these organisms come they begin to grow, 

 and we find them spreading from the first initial point to other 

 parts of the body. During the early stages of the disease the 

 progress is nearly always slow. We may kill animals that react 

 to tuberculin and find only two or three little tubercles : we may 

 kill others that have not been diseased any longer and may find 

 great masses of tubercular growth. There is no uniformity in 

 the way in which the disease spreads in the animal. The condi- 

 tions under which the animal is kept have much to do with the 

 progress of the disease. But the tendency is always towards 

 progress and not towards recovery. The disease is an extremely 



