ADDENDUM 



All were purchased from retail traders, and for most the age was 

 unknown. 



For the tubercle bacillus test 84 guinea-pigs were infected 

 intraperitoneally from 21 of the 25 samples. The remaining four 

 samples were not tested because they were known to come from 

 pasteurized cream. Two of the guinea-pigs developed tubercu- 

 losis, a percentage of 9'5. Antiformin was used to destroy 

 extraneous bacilli in a few cases, but the authors remark " it is 

 doubtful whether the use of antiformin is serviceable in this 

 connection." 



The number of bacteria (agar plates at 37 C.) found per grm. 

 of butter averaged 2,700,000 for the salted butters and 30,000,000 

 for the unsalted butters. The lowest count was 8600 and 

 17,000,000 the highest for the salted and 41,000,000 for the 

 unsalted. The wide variations in the bacterial count were 

 apparently not associated with any other constituent deter- 

 mined, such as salt, acidity and moisture. Like earlier 

 investigators they found the bacterial content largely influenced 

 by the age of the butter. All the samples examined within a 

 few days of being made contained from one to several million 

 bacteria per grm., while all the low counts were from butters 

 which had been sent for some distance or which were of uncer- 

 tain age. 



This question was directly tested in a few cases. In one 

 sample there was a reduction of 85*8 per cent, in two weeks, in 

 another 937 per cent, in four weeks and in another 95*6 per 

 cent, in six weeks. 



B. coli was found in only 6 of the 25 samples when O'Oi grm. 

 or less was examined, and then only in small numbers. From 

 a few special experiments made it seems that this bacillus soon 

 dies out in butter. 



Streptococci were found in 14 of the 25 samples in 0*01 grm. 

 No special relation between the presence of streptococci and 

 virulence to guinea-pigs could be made out. 



B. welchii (B. enteritidis sporogenes) was absent from I grm 

 of all the 25 butters. 



