FATE OF TUBERCLE BACILLI OUTSIDE THE ANIMAL BODY 359 



General Summary 



A summary of the results showing the length of time that 

 tubercle bacilli from various materials live in water is given in 

 Table 29. 



Conclusions 



1. Tubercle bacilli live for more than a year (441 days) in 

 running water. 



2. The length of time that human and bovine tubercle bacilli 

 live in water is practically the same. 



3. These organisms live in sputum exposed in water for more 

 than 232 days. 



4. They live in the tissues of a dead guinea pig exposed in 

 water for more than 321 days but are dead in 381 days. 



5. A watering trough harboring tubercle bacilli may become a 

 dangerous source of infection to cattle. 



6. A dead tuberculous animal in a stream on your neighbor's 

 farm may be a means of infecting your stock. 



7. The better disposition of dead tuberculous animals is to 

 destroy by burning. 



8. Tubercle bacilli in drinking water is one of the possible 

 sources of infection for man. 



9. Infection is not prevented by dilution, since clumps contain- 

 ing a great number of these organisms may be inclosed in mucoid 

 material which prevents their separation and destruction. 



DURATION OF LIFE OF BOVINE TUBERCLE BACILLI IN BUTTER 



INTRODUCTORY Considerable attention is at present being directed 

 STATEMENT to the presence of tubercle bacilli in foods, more 

 especially milk, butter and cheese. It has been 

 determined by Sedgwick and Winslow and by Park that typhoid 

 bacilli frozen in water die very rapidly. After an hour's freezing 

 30 to 60 percent were destroyed, and in two weeks 99 percent were 

 killed. The remaining one percent lived for a number of weeks. 

 Tubercle bacilli in butter kept at a temperature below freezing are 

 not killed in this, way, as determined by Mohler, Washburn and 

 Rogers in 1909. In order to obtain further information upon this 

 subject the following experiments were planned. 



Butter was mixed with an emulsion of a pure culture of bovine 

 tubercle bacilli and placed in small vials which were stored in the 

 three following places: 



