Contamination of Milk. 41 



Dairymen have learned many of these lessons in the 

 severe school of experience, but the reason for the same 

 is so palpably plain in the light of bacteriological explana- 

 tion, that further discussion would seem unnecessary. It 



FIG. 10. Bacterial content of milk drawn with care. Diminished germ con- 

 tent is shown by smaller number of colonies (330 bacteria per cc.). Compare 

 this culture with that shown in fig. 9. 



remains to be seen whether the words of the eminent 

 German authority, Prof. Fleischmann will much longer 

 prove true, when he says that "all the results of sci- 

 entific investigation which have found such great prac- 

 tical application in the treatment of disease, in disinfec- 

 tion and in the preservation of various products, are 

 almost entirely ignored in milking. " 



43. Effect of temperature on bacterial growth. 

 After milk is once seeded with bacterial life, no one factor 

 exerts so potent an effect upon the rate of change that 

 takes place as that of temperature, for the rapidity of 

 bacterial growth in milk is determined mainly by this 

 factor as is seen in fig. 11. 



