ADDENDUM 189 



48 were foreign samples received from the Board's Inspectors 

 of Foods. Of these 4 yielded inconclusive results, while none of 

 the remaining 44 were found to be tuberculous. 



The " inconclusive " results were the cases in which prema- 

 ture death of the guinea-pigs was caused owing to the high 

 infectivity of these butters for these animals. Excluding these 

 butters 2 out of 82 (2*4 per cent.) were found to contain tubercle" 

 bacilli. 



In no cases were acid fast bacilli, other than the tubercle 

 bacillus, found in animals inoculated with the fat-free deposit, 

 but these organisms were found in a number of cases when 

 guinea-pigs were inoculated either with the clear melted fat or 

 with material containing an admixture of fat. 



Rosenow, Frost and Bryant 1 have recently published a paper 

 on a study of the Market Butter of Boston, U.S.A. 



In their method of examination for bacteria, B. coli, etc., 

 I grm. of butter was withdrawn by sterile spatula and mixed 

 with 100 c.c. of sterile tap water at 40 45 C. in a jar. While still 

 warm the jar was shaken for 1 5 minutes in a shaking machine. 

 To make the required dilutions I c.c. of this emulsion was 

 quickly transferred to a flask containing 100 c.c. of sterile water. 

 From this further dilutions were made in the ordinary way. 



For testing for the tubercle bacillus various quantities were 

 used. Some of the guinea-pigs received the butter itself, others 

 were inoculated with washings or sediment obtained from 

 centrifugalising the washings, and some with both butter and 

 sediment. The majority received the sediment from 50 grms. 

 of butter. For this purpose the authors suggest that the best 

 method is to shake the bacteria out of the butter by violently 

 agitating 50 grms. in warm water in a shaking machine. The 

 mixture is rapidly cooled, the water and bacteria poured off and 

 centrifugalised and the sediment used for the animal inocula- 

 tion. 



The authors investigated the bacteria washed out from the 

 butter and found that 83 to 99 per cent, (average 90*4 per cent.) 

 were removed in the first washing. 



25 butters were examined, all in the months of June and July. 



1 The Journal of Medical Research) 1914, XXX, p. 69. 



