142 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



regular part of their food that they have stopped its use and 

 cannot be persuaded to even taste a glass which they are 

 absolutely sure is pure in every way. ' ' A burnt child dreads 

 the fire," and many who have had an unpleasant experience 

 with milk, dread it in any form. Some people who recognize 

 that milk is a necessity regard it almost as a medicine and use 

 it accordingly; as soon as the baby is old enough, other food is 

 substituted and milk is used only by the spoonful. 



Some intelligent and careful dairymen have recognized that 

 the two causes just named are the ones which operate strongly 

 against their business; they have taken advantage of these facts, 

 handled their dairies accordingly and to every appearance they 

 are well rewarded for their foresight and good business ability. 

 Their methods will bear examination, study and repetition. 



It should be remembered that the production and handling 

 of milk Is no longer a rule of thumb occupation, it is a science, 

 and this science has developed and broadened greatly within the 

 past few years and is still developing at a rapid rate. Formerly 

 the dairymen performed his work always in the same manner 

 because he knew by experience that certain results would follow, 

 little was known of causes or effects, and with such a poor 

 understanding of his work, not a -great deal could be expected 

 in the way of improvement or successfully dealing with changed 

 conditions. 



Successful dairying is intimately connected with several 

 sciences and one of the most important of these and the latest 

 to be understood is bacteriology. This science has done much 

 to explain the changes of milk, just what causes them, how 

 they may be checked and how they may be avoided. It 

 teaches us that very small organisms, called germs or bacteria, 

 are the cause of milk becoming sour or otherwise changing. 

 There are many kinds of bacteria and the different species pro- 

 duce different effects when they get into a substance in which 

 they can grow. The sour milk bacteria is the most common in 

 the dairy, but they are not the only ones; some make milk 

 ropy, others produce colors and many cause less marked changes. 



They are all objectionable, so far as is known, in milk 



