I 12 



STORRS AGRICULTURAL EXPERIMENT STATION. 



the open pail. The following table summarizes the results of 

 some tests in which the time of curdling and percentage of 

 acid were observed in samples in which the quantity of dirt 

 was also determined. 



Table 59. 



Comparison of quantities of dirt, time of curdling and percentage 



of acid in milk from opeti atid covered pails. 



From the table above it will be observed that while in the 

 average of the three tests the milk from the covered pail con- 

 tained only about 35 per cent, as much dirt as that from the 

 open pail, the former curdled sooner than the latter, and at the 

 time of curdling contained a higher percentage of acid than the 

 milk not curdled. 



It would appear then that in these samples the milk which 

 contained the least dirt kept the shortest time. 



the relation between the amount of dirt in the milk 

 and the germ content. 



In several of the samples in which the quantities of dirt 

 were determined, tests were also made of the numbers of bac- 

 teria in the fresh milk and in the same milk after being kept 

 fifty hours at ordinary temperature. For this purpose plate 

 cultures were made, as in the experiments described by Conn 

 and Esten on preceding pages, and on the plates the total 

 number of bacteria per cubic centimeter as well as the number 

 of acid and liquefying organisms were determined. The fol- 

 lowing table gives the results of these determinations: 



