16 



BULLETIN 139, IT. S. DEPARTMENT OF AGRICULTURE. 



were present in • T ^ ir of a cubic centimeter. Only 9 samples showed 

 organisms of the colon-aerogenes group, and 8 of these ranged from 

 100 to 2,000, while the other had a count of 28,000 per cubic centi- 

 meter. Further study of the disks shows that there is no correlation 

 between the quantity of manure and the colon count; some samples 

 having a considerable amount of sediment showed no organism of the 

 colon-aerogenes group, while others with a considerably less amount 

 showed several hundred per cubic centimeter. 



Reference to column C of figure 1 shows that about 72 per cent of 

 the samples of milk produced under the conditions described did not 

 contain any organisms of the colon-aerogenes group in y^- of a cubic 

 centimeter. Table 8 gives the results of a series of samples in which 

 larger quantities of milk were examined. It is evident that milk, 

 when fresh, even though produced under extremely dirty conditions 

 and handled in unsterilized utensils, contains only a few organisms of 

 the colon group. Of the 38 samples, 1 1 showed no colon organisms in 

 ^ of a cubic centimeter of milk, while in the remaining 27 samples 

 the minimum colon count ranged from 3 to 75 per cubic centimeter. 



Table 8. — Small colon-aerogenes injection in fresh milk produced under dirty conditions. 



Sample 



Total 



Colon 



Sample 



Total 



Colon - 



No. 



count. 



count. 1 



No. 



count. 



count. J 





Per c. c. 



Per c. c. 





Per c. c. 



Per. c. c. 



1 



179, 000 







20 



580,000 , 



5 



2 



180,000 







21 



620, 000 



50 



3 



182, 000 



10 



22 



630, 000 







4 



190, 000 



5 



23 



680, 000 



50 



5 



225, 000 



10 



24 



750, 000 







6 



260, 000 



10 



25 



790, 000 



75 



7 



270, 000 



10 



26 



820, 000 



8 



8 



295,000 



8 



27 



840, 000 







9 



304, 000 



10 



28 



1,080,000 



10 



10 



318, 000 



10 



29 



1, 120, 000 



10 



11 



320, 000 







30 



1, 170, 000 



8 



12 



340, 000 







31 



1,310,000 



3 



13 



366, 000 







32 



1,320,000 



3 



14 



450, 000 



5 



33 



1, 440, 000 



5 



15 



460, 000 







34 



1, 450, 000 







16 



490, 000 



3 



35 



1, 600, 000 







17 



490, 000 



10 



36 



1,940,000 



10 



18 



497,000 



8 



37 



1,950,000 



10 



19 



560, 000 



75 



38 



2,400,000 



10 



1 Cipher indicates no organisms of the colon-aerogenes group in T * cubic centimeter of milk. 



Additional sediment disks are shown in Plate III, the correspond- 

 ing samples of which are also included in column D of figure 1 . In this 

 case the utensils were not washed till 8 hours after milking, but 

 otherwise the conditions were the same as in the previous experi- 

 ment. Here, again, even with very large quantities of manure found 

 in the milk, together with the increased possibilities of colon con- 

 tamination from the unsterilized utensils, the colon count never 

 ran over 2,000 per cubic centimeter when the milk was fresh. Plates 

 I, II, and III show that under these conditions there is no definite 



