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QUALITATIVE ANALYSIS OF MARKET MILK. dhe 
column the total numbers of bacteria in different samples tested, 
arranged in the order of their size. In the second column is 
given the percentage of acid bacteria in each sample, only 
Groups I. and II. being included, and in the third column ap- 
pears the percentage of liquefiers. 
A glance through the figures will show that although there 
is no regular increase in the percentage of acid organisms as 
the numbers rise, a general increase is very clear. ‘The larger 
per cents. of acid organisms are found only in the Samples where 
the numbers of bacteria have become somewhat large. No 
sample which shows more than 50 per cent. of the acid organ- 
isms contained less than 250,000 to 300,000 bacteria, and the 
only samples where the acid organisms were as high as go per 
cent. were three in each of which the total number of bacteria 
was in excess of 500,000. On the other hand, in all of the 
samples where the percentage of lactic organisms is small, be- 
low 10 per cent., the number of bacteria is correspondingly 
small, in few cases rising to more than 50,000 per cubic centi- 
meter. ‘This conclusion is quite in accordance with the facts 
brought out in a previous paper, that with increase in the age 
of the milk there is, along with the actual increase in numbers 
of bacteria, a very noticeable increase in the percentage of lac- 
tic bacteria. The conclusion is that a large per cent. of acids 
must indicate, in all probability, that the milk is somewhat old 
or has been kept under moderately warm conditions. 
It must, however, be noticed that this parallel does not al- 
ways hold, and that there are some samples in which the per- 
centage of acids and the total numbers do not increase together. 
‘In experiment No. 18 the total number of bacteria was quite 
high, 100,000, while the acid organisms in this case were very 
few in number, only .8 per cent. In this sample the cows 
were fed with a considerable quantity of grass and ensilage, 
and probably this fact somewhat modified the conditions; while 
the abundance of liquefiers rendered the detection of acid col- 
onies difficult. Probably some of Group IV. were really lactic 
bacteria. ‘Ihe same results can be seen from experiments Nos. 
10 and rr, in which tolerably high total numbers of bacteria 
show only moderately low percentages of lactic organisms. 
Asa converse to the last conclusion, it will be noticed from 
Table 13 that milk containing small total numbers of bacteria 
