lactic acid had been produced to cause the curdHng of the milk. 

 On the morning of the third day the acidity showed a marked in- 

 crease and a general curdling had taken place. In some few cases 

 curdling did not actually occur until the fourth day, although the 

 milk had a disagreeable odor. The milk produced by the experi- 

 ment station showed very little change in acidity until the beginning 

 of the third day, and none of the several samples curdled until the 

 fourth day. 



Lactic acidity being due to the action of lactic acid germs does 

 not necessarily indicate a dirty milk. Any appreciable degree of 

 acidity above the normal (13° to 20°) would be an evidence of old 

 milk, or it might indicate that the milk had not been properly protect- 

 ed from dirt or dust, or that it had been kept at too high a tempera- 

 ture. Because of the normal acidity of the milk when first tested, 

 and because most of the milk did not sour for 36 hours thereafter, 

 one may safely conclude that the larger part of the product was not 

 over 12 to 24 hours old at the time of collecting the samples. The 

 two samples of milk known to have been watered tested 10.3° and 

 11.2°, and one very suspicious tested 10.4°. It seems quite 

 probable that milk testing 1 1° or lower has received more or less 

 water. 



2. C/ieniical Analysis of the Milk. 



The analyses of the samples reported in the following table were 

 made in the usual manner. The fat was determined by the Babcock 

 method, the total solids by evaporation on sand, and the solids not 

 fat by difference. 



