26 THE BACTERIAL TEST 



dipper, or anything unsterilized which the milk 

 touches will spoil the sample. 



(2) The sample is kept ice-cold until tested, 

 otherwise the bacteria will multiply. 



DILUTING THE MILK WITH STERILE WATER 



(3) In the laboratory exactly i cc. of milk 

 (about a thimbleful) is drawn out of the sample 

 with a glass tube and discharged into a bottle 

 of sterilized water so as to make a dilution of 

 I per cent. If the milk is believed to contain 

 large numbers of bacteria, the dilution is made 

 higher. 



