178 PRACTICAL DAIRY BACTERIOLOGY 



1. The methods of analysis can never be of value in con- 

 demning any particular sample of milk, but only in giving con- 

 demnation of the dairy that produces the milk or the dealer 

 who distributes it. It usually requires 24 hours before the 

 number of bacteria can be determined, and before this the milk 

 has, of course, been consumed. Even if the number of bacteria 

 can be obtained two or three hours after the sample is received, 

 it is quite too late to prevent the distribution and consumption 

 of any particular sample of milk. All that can be done then is 

 to condemn all of the milk from a certain source on the ground 

 that one or two of the samples of milk have shown a number 

 of bacteria above a certain standard. This is, of course, an 

 unsatisfactory method of dealing with the question, but it is 

 really the only possible one. 



2. The use of a numerical standard is likely to be extremely 

 unfair, condemning milk from some sources that should not be 

 condemned and passing milk from other sources that should not 

 be passed. A numerical standard, as we have just seen, is 

 simply a somewhat indefinite gauge of filth, temperature and 

 age combined. One dairy may have conditions of the most ex- 

 treme slovenliness, and yet the proprietor is shrewd enough 

 to cool the milk to a low temperature by the use of ice and thus 

 check the development of bacteria. Under such conditions, 

 though the milk is filthy and the conditions that surround his 

 dairy are most unwholesome, the milk would readily pass the 

 inspection, because the simple use of ice has prevented the 

 bacteria from developing. The milk is likely to contain much 

 that renders it unwholesome, but it will pass inspection. On 

 the other hand, a dairy at a little greater distance from the city 

 might be kept under conditions of scrupulous care in the milk 

 production, and yet because of the use of less ice and thus less 

 cooling, the milk before reaching the city would contain large 

 numbers of lactic bacteria. Such milk would be condemned, 

 and yet it would have nothing unwholesome in it. For it must 



