TYPHOID FE\^R 111 



accident is necessary to afford an indirect or direct 

 means of carrying typhoid bacilli into the water or milk. 



The typhoid bacillus can multiply rapidly in milk 

 and greatly increase in number in the course of a short 

 time, it resists the commencement of acid formation but 

 is partly checked and killed by great acidity; yet it is 

 not certainly killed by the degree of scouring to which 

 cream is subjected before churning. Bolley and Field 

 have found that typhoid bacilli will live at least ten days 

 in butter [and Bruck has shown that they were virulent 

 after 27 days]. Hence, not only milk and cream but 

 also buttermilk (epidemic in Hamburg; Friinkel and 

 Koster), newly made butter and fresh cheese may be 

 bearers of virulent typhoid bacilli. The typhoid bacillus 

 is destroyed by pasteurization at <S0° C. (17()' F.) and 

 heating for a few minutes at 70 ' to 7.j C. (l.'S to 1(57' 

 F.) will kill it. C*are must be taken to heat the whole 

 volume of milk to this temperature. (See " Pasteuri- 

 zation.") 



In pure culture, the typhoid Ijacillus does not change 

 the appearance of milk and alters its reaction but little. 

 It is very difficult to detect it in milk, as it is in drinkin 

 water, for its colonies in gelatin are very similar to 

 those of the colon bacilli. To detect it, the milk must be 

 sown in the usual method in gelatin plates and then as 

 great a number as possible of susi^icious colonies iso- 

 lated. These are then implanted in fermentation bulbs 

 in bouillon, some of which contain grape sugar and some 

 sugar of milk. Those forms which cause an acid reac- 

 tion in the milk sugar bouillon or those which ferment 

 the grajje sugar with the formation of gas or which do 

 not change the reaction of the grape sugar bouillon are 

 to be rejected. Only those cultures which give a strong 

 acid reaction without jiroducing gas in the grape sugar 

 bouillon, are really suspicious and these must be sub- 



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