STUDIES OF MARKET MILK. 193 
the milk contained on any day is 26,870 on December 2d. 
From this relatively low number the germ content runs up to 
_ 2,831,000 on September 16. This is a higher number than 
was found in any of the samples in either group1or2. ‘The 
percentage of acid organisms is also higher in this case than 
any of those discussed up to this point. The variation in the 
percentage of acid organisms runs from 16 up to 99 while the 
average for the entire series of experiments is 58.4 per cent. 
This increase in the proportion of acid organisms indicates that 
the milk was either quite old or else had been kept at such 
warm temperatures that the bacteria had multiplied with great 
rapidity by the time the milk was delivered. In fact the milk 
of this producer was not infrequently sour when delivered and 
was rejected by the shippers. Producer No. 15 stopped send- 
ing his milk to the shipping station after a few samples had 
been obtained. The figures given in Table 39 present no 
striking features worthy of discussion at this point. The aver- 
age germ content of his milk places it in this group. ‘The dirt 
content is rather high, the average percentage of acid organ- 
isms is lower than for many of the other men. As already 
stated the chief difference in regard to these two producers is 
the somewhat greater germ content than is found in the pre- 
ceding groups. 
Discussion of group 4.—In this group are placed the results 
obtained from the milk which showed an average number of 
bacteria between 1,000,000 and 2,000,000 per cubic centimeter. 
The milk of seven men comes within these limits. This is 
23.3 per cent. of the entire number of producers whose milk 
was being studied. The milk of these men was delivered at 
the shipping station at the same time as that contained in the 
preceding groups. The increased germ content must, there- 
fore, be due to some other cause than the greater age of the 
milk. This cause is manifestly the difference in conditions 
under which the milk was produced and handled. A study of 
the total numbers as given in the different tables in this group 
shows a large variation from day to day and in some cases 
the germ content was relatively very low, being as low as 
6,169 on November 18, Table 40. On December 20 the 
milk of the same man showed a germ content of considerably 
