186 MASS. EXPERIMENT STATION BULLETIN 187. 



Table XIV. — Does an Increase in Dirt Mean an Increase in Bacteria 

 in Clarified Milk and Water? 



1. Determine by adding definite quantities of dirt to water, and esti- 

 mate number of bacteria per cubic centimeter before and after clarifica- 

 tion. 



2. Determine by adding similar quantities of dirt to milk, estimating 

 the number of bacteria per cubic centimeter before and after clarification. 



Adding .5000 Gram of Dirt to Milk Containing 100,000,000 Bacteria per Cubic 



Centimeter. 



Adding .2000 Gram of Dirt to Milk Containing 15,000,000 Bacteria per Cubic 



Centimeter. 



Sample III, 



50,000,000 



8,000,000 



Adding .1000 Gram of Dirt to Milk Containing 22,000,000 Bacteria- per Cubic 



Centimeter. 



Sample IV, 



40,000,000 30,000,000 



A determination of the solubility of dirt was undertaken to set before 

 the reader just the nature of the dirt problem. The first series of deter- 

 minations was made by placing a combination of dry manure, curryings 

 and dust of definite weight, which might get into milk easily, into water 

 as a menstruum, then the suspension and solution were filtered or clarified. 

 Later, milk was employed as a menstruum in place of water. 



