306 DISTRIBUTION OF BACTERIA 



sidered the highest grade of milk on the market, namely, cer- 

 tified milk, the number is usually limited in the contract to 

 ten thousand bacteria per cc., and, practically, a considerable 

 amount of this milk is delivered to the home of the consumer 

 with only a small fraction of this number present. Other 

 milk collected under less ideal conditions, but constituting 

 what would be considered a good milk, has tens or hundreds of 

 thousands of bacteria per cc. A number of cities have limited 

 the number of bacteria permissible in good milk to two 

 hundred and fifty thousand, and others to five hundred 

 thousand. 



A good many milks produced under poor conditions, or 

 kept, after being collected, for long times under unfavorable 

 conditions, contain enormous numbers of bacteria. For in- 

 stance, Park found in New York City an average in twenty 

 samples 5,669,850 bacteria per cc. as the milk was received in 

 the city. 



From tenements, midwinter, 1,977,692. 



From well-to-do districts, midwinter, 327,500. 



From tenements, Sept., 15,163,600. 



From well-to-do districts, 1,061,400. 



The Source of Bacteria in Milk. Attention has already 

 been called to the initial bacterial content of milk, and it 

 perhaps ought to be added that the attempt is sometimes made 

 to reduce this by discarding the fore milk, or the first few cubic 

 centimeters drawn from each teat, but while there are more 

 bacteria in the fore milk than in other parts of the milking, 



