DAIRY MEETING. 1 75 



tuberculosis, glanders and many other contagious diseases to 

 which man and beast are heir. 



We are interested now only in those that occur in milk, but 

 these are numerous enough and troublesome enough, for, if we 

 could get rid of them, we would be able to have milk that would 

 keep without souring, and there would not be the usual summer 

 outbreaks of infantile intestinal diseases. Neither would we 

 see the more and more numerous reports of epidemics of scarlet 

 fever, typhoid fever and diphtheria that are appearing in our 

 medical journals. In other words, we would have a milk that 

 would keep sweet and be always healthful, for both the keeping 

 and sanitary qualities of a milk are directly proportionate to its 

 germ content. It is, then, of interest to us to determine the 

 source of these troublesome organisms, and to learn how to 

 eliminate them as far as possible, and, where it is impossible to 

 eliminate them, to control their chance of entering the milk, and 

 to keep those that do enter it from multiplying. 



Before going farther we should get a few facts in regard to 

 the habits of bacteria in general, which will help us to under- 

 stand both the part they play in entering milk, and how they may 

 be excluded from it in greater part. 



Bacteria are not organisms possessing invisible wings. Of 

 their own accord they do not fly about in the air, looking for a 

 chance to cause trouble. Some of them have powers of locomo- 

 tion when in liquids or on solids ; but if they go any distance 

 from their point of birth it is because they are carried by some 

 outside agency. They are heavier than air and so, if the air is 

 quiet, they will gradually settle out of it. However, they are so 

 very little heavier than the air that, like the toy balloons of our 

 country fairs, any movement of the air will keep them afloat 

 for a long time, unless they are attached to heavier particles of 

 dust or dirt, which drag them down. 



Another fact of importance is that bacteria do not spring into 

 being spontaneously and live on faith. They must have organic 

 matter of some kind to live upon, and all kinds of dirt about a 

 stable furnish this food in abundance. When they do have this 

 necessary food they thrive and multiply with great rapidity. 

 One typhoid germ will in 24 hours produce 17,000,000 of its like. 

 jMillions live and grow on a single dirty cow's hair, and manure 

 dust is laden with their hosts. Couple these facts with the ad- 



