ILLINOIS STATE DAIRYMEN'S ASSOCIATION. Ill 



It is a well-known fact that a certain amount of heat 

 is necessary to all vegetable growth. Tt is also well-known 

 that a certain temperature will produce certain growths, and 

 that vegetation will only reach its perfection being in the 

 proper temperature long enough to reach maturity. 



This can be illustrated by planting some of the tropical 

 fruits in our Northern climate. A pine apple, lemon or 

 orange will grow during the very warm w^eather with as much 

 vigor and speed as it does in its native climate, but the first 

 frost not only checks growth, but destroys the possibility of 

 its reproducing itself. We must bear in mind that the object 

 of all vegetable growth is reproduction and multiplication. 

 We look with wonder at vegetation lying dormant almost half 

 of the year, and at the rapidity with which it takes on life, grows 

 and multiplies when spring brings the proper conditions. 



Now there is an invisible vegetable growth all around 

 u<^^ just as wonderful, if not more wonderful, than the one 

 we see. It springs into life when the proper temperature 

 and conditions permit and lies dormant when they do not. 

 Their growth is so rapid that thousands of them will be pro- 

 duced in a few minutes with proper surroundings. Some of 

 them are found everywhere at all times, others only under 

 special conditions. 



Most of them are of the utmost importance to us when 

 in their proper place; others always harmful wherever found. 



These bacteria are invisible plants, or at least most of 

 them, thrive best and reproduce fastest at a temperature of 

 80 to 100 degrees, or the ordinary temperature of milk when 

 it comes from the cow. It is a well-known fact that no matter 

 how tidy or clean a cow stable may be kept, it is never free 

 ficm these bacteria and it is impossible to milk a cow with- 

 out having them fall into the milk. There is probably no 

 substance except w^hen it has been especially prepared, (such 

 as beef tea), where these bacteria will grow so readily as 

 fresh warm milk. These bacteria are harmless in them- 

 selves. It is the change they produce in the milk that is 

 injurious. 



The quickest and best method known to stop the growth 

 of bacteria in milk is to cool it as quickly as possible after 



