138 BACTERIA IN DAILY LIFE 



curiously, a particular effect upon tubercle bacilli 

 present, for Professor Scheurlen has found that 

 they are nearly all left in the slime. Naturally 

 his observation was not slow in being tested by 

 other investigators ; but Professor Bang has quite 

 independently confirmed Scheurlen's discovery, 

 and, still more recently, Moore purposely infected 

 milk with these bacilli, and found that they were 

 deposited in the slime to a most remarkable 

 extent. Coupled, however, with this peculiar 

 behaviour of tubercle bacilli in separated milk is 

 the fact called attention to by Ostertag, that 

 tuberculosis is much more prevalent among swine 

 in Denmark and North Germany, where the centri- 

 fugal process in creaming is extensively used, and 

 where, until recently, this slime was given to the 

 animals in its raw, uncooked condition. 



Before leaving this subject of separated milk, 

 reference may be made to a danger, which has 

 recently been publicly called attention to, sur- 

 rounding the use which is made of skim milk. 

 By an arrangement with the farmers who supply 

 the milk, those clients who principally use it for 

 producing butter return the skim milk to them 

 after it has been through the separator, when it is 

 employed for stock-feeding purposes. The milk 

 in large dairies derived from different farmers is 

 mixed, and hence the skim milk which is re- 



