i6 



I. Acidity of Market Milk. 



Freshly drawn milk possesses a slight amphoteric (acid and alka- 

 line) reaction, due to the presence of acid and neutral phosphates, 

 alkaline carbonates and free carbonic acid. Fresh milk is free from 

 lactic acid which is a product of fermentation. Richmond states 

 that IOC cubic centimeters of fresh milk require about 20 cubic cen- 

 timeters of i-io normal sodium hydrate to neutralize it, and the num- 

 ber of cubic centimeters required he designates •' degrees of acidity.'" 

 Most of the samples collected were tested at different times for acidity, 

 the first test being made in the afternoon of the day of collection. 

 During the entire time they stood in the laboratory where the temp- 

 erature was from 70° to 80° Fahr. 



' Milk from different cows varies somewhat from this figure. Only lo c. c. of milk were 

 used in the present investigation, so that the results presented have been multiplied by lo. 

 It is possible that had more than lo c. c. of milk been used, the results might have differed 

 slightly. They are at least comparative. 



