190 MASS. EXPERIMENT STATION BULLETIN 187. 



It is legitimate to claim that the cotton disc in the Wisconsin Sediment 

 Tester is as good a strainer as is employed, but it is not wholly efficient. 

 The clarifier removes insoluble dirt which has not been removed by the 

 tester. Again, the clarifier removes insoluble dirt to such an extent when 

 running within its prescribed limitations that it is impossible to detect 

 it by any methods used by the investigators. Of course, dirt which has 

 gone into solution is beyond reclamation. It is doubtless true that the 

 clarifier is the most efficient strainer known when the specific gravity of 

 the dirt is not lighter than the milk. It practically removes all- insoluble 

 dirt. 



Micro-organisms in Slime. 



It is possible to study the number of micro-organisms in the slime 

 eliminated from milk as well as the number of micro-organisms before and 

 after clarification. It would be better to use the slime in this determina- 

 tion were it feasible to release the micro-organisms from the slime, since 

 in the determination before and after clarification colonization with its 

 difficulties interferes to such an extent as to vitiate the results. 



To demonstrate this difficulty in the release of micro-organisms from 

 slime, and at the same time to indicate the micro-organisms elimmated 

 from milk which do not reveal themselves in the counts before and after 

 clarification, the following tables are introduced. In these efforts it is 

 doubtful whether 50 per cent, have been made available for counting. 



