240 MILK AND THE PUBLIC HEALTH ch.xiv 



While complicated in interpretation, the results are 

 extremely simple to record in actual work. Two examples 

 may be given : 



1. Byre Milk. — In a sample, four of the 1 c.c. L.B.B. tubes are 

 positive, wliile the fifth and the two O'l c.c. tubes are negative. 



In 5 c.c. of milk = 4 lactose fermenters. 



5) -^ jj ;» ^^ O o ,, „ 



By using the table given the same result can be read off without any 

 calculation. 



Such a finding would be recorded as unsatisfactory in summer, and 

 sufficient to condemn in winter. 



2. Vended Milk. — In a sample the A and B and three of the tubes 

 are positive, while the remaining C tube and the four D tubes show no 

 acid or gas. 



In 0-004 c.c. of milk = 3 lactose fermenters. 

 J) -^ )) )J ^^ /oU ,, „ 



The sample contains 750 to 1000 lactose fermenters per c.c. — a 

 result which could be directly read ofl: from the table. 



Such a finding would pass the sample in summer, but condemn it in 

 winter. 



