BACTERIOLOGY OF MILK IN ITS RELATION TO DISEASE 463 



into which the cans of milk are placed soon after milking. In winter 

 these methods are very satisfactory, for the water runs into the pipes 

 or tanks at about 38 F. In warmer weather they are unsatisfactory, 

 unless ice is used, as the natural temperature of the water may be. as 

 high as 55 F. A considerable quantity of milk is not cooled at all at 

 the farms. It is sent to the creamery or railroad after two to six hours, 

 and is then more or less cooled. These few hours in summer, when 

 the milk is left almost at blood heat, allow an enormous development 

 of bacteria to take place, as is shown in the table below. 



TABLE I. Showing the development of bacteria in two samples of milk maintained 

 at different temperatures for twenty-four, forty-eight, and ninety-six hours, respectively. 

 The first sample of milk was obtained under the best conditions possible, the secoud in 

 the usual way. When received, specimen No. 1 contained 3000 bacteria per c.c., speci- 

 men No. 2, 30,000 per c.c. 



Time which elapsed before making test. 



Temperature. 

 Fahrenheit. 



32 



39 



42 



46 C 



50 



55 C 



60 



68 C 



86 C 



48hrs. 



2100 



27,000 



3600 



56,000 



3600 



210,000 



12,000 



360,000 



540,000 



1,940,000 



3,400,000 



38,000,000 



28,000,000 



168,000,000 



96hrs. 



1850 



24,000 



218,000 



4,300,000 



500,000 



5,760,000 



1,480,000 



12,200,000 



300,000,000 



1,200,000,000 



168 hrs. 



1400 



19,000 



4,209,000 



38,000,000 



11,200,000 



120,000,000 



80,000,000 



300,000,000 



24hrs. 

 2400 

 30,000' 

 2500 

 38,000 

 2600 

 43,000 

 3100 

 42,000 

 11,600 

 89,000 

 18,800 

 187,000 

 180,000 

 900,000 

 450,000 

 4,000,000 

 1,400,000,000 

 14,000,000,000 



Observations on Bacterial Multiplication in Milk at 90 F., a Temperature Common 

 in New York in Hot Summer Weather. 



Milk I. 



Fresh and of good 

 quality. 



Original number 



After two hours 



" four " 



" six " 



" eight " 



TABLE II. Number of Bacteria per 1 



Milk II. 



Fair quality from 

 store. 



5200 



8400 

 12,400 

 68,500 



654,000 



92,000 

 184,000 

 470,000 

 1,260,000 

 6,800,000 



Milk III. 

 Bad quality from 

 store. 



2,600,000 



4,220,000 



19,000,000 



39,000,000 



124,000,000 



A sample of milk No. I. removed after six hours and cooled to 50 F. contained 

 145,000,000 at the end of twenty-four hours. Some of this milk, kept cool from the 

 beginning, contained but 12,800 bacteria per c.c. at the end of twenty-four hours. 



The figures referring to tests of the second sample are printed in heavy-face type. 



