122 Report of the Department of Bacteriology of the 



tion. As matters stand they cannot be accepted as members of 

 the udder flora with the same feeling of certainty which accom- 

 panies the other forms. 



Temperature relations. — By referring to Table X it will be seen 

 that certain numbers in the table are printed in bold face type, 

 which signifies that these forms did not appear on the plates kept 

 five days at room temperature but did appear after these plates 

 had been held two additional days at 37° C. This would indicate 

 that these particular forms had become so habituated to the blood 

 heat of the cow as to grow rather poorly at lower temperatures. 



The distribution of this class of organisms is also interesting. 

 They are lacking in Carey F., Hammond F. No. 2 and Millie 

 F. B. B., make up the entire flora in Hammond No. 2 and are 

 present in varying proportions in the other udders. 



A partial explanation of this temperature relation is found 

 by studying the udders in which there is a mixed result, as with 

 Millie D. Here the examinations extended over a year and it 

 will be observed that the additional growth at 37° C. was mainly 

 during the colder portions of the year. While the temperature of 

 the room in which the plates were held for five days was main- 

 tained at approximately 70° F. during the day the temperature 

 fell sharply at night with the result that the growth of these udder 

 germs was markedly checked. These irregular results due to in- 

 cubation at room temperature emphasize the weakness of this 

 procedure and the need of a low temperature incubator such as 

 has been constructed and will be described in a forthcoming 

 bulletin. (Technical Bulletin No. 29.) 



It is clear, however, that the above is not an entire explana- 

 tion of this temperature relation since the tests with Carey F., 

 where the high-temperature-loving forms were absent and with 

 Hammond No. 2, where they made up the entire flora, were made 

 simultaneously. 



RELATION OF UDDER FLORA TO MILK PRODUCTS. 



Practically the only extended study of milk products which is 

 available for direct comparison is that of the flora of cheddar cheese 

 as given in Technical Bulletin 8. 20 At that time the Society 



20 Hard in <*, H. A., and Prucha, M. J. The bacterial flora of cheddar cheese. 

 N. Y. (State) Apr. Exp. Sta. Technical Bulletin S. 1908. Also in Ann. 

 Rpt. of same Station 27 (1908): 48-120. 1909. 



