46 BACTERIA IN DAILY LIFE 



directly they were discarded, in another series 

 of investigations they were collected and kept 

 in a dry place for from fifteen to twenty days 

 before being tested; but even storage for this 

 length of time did not prevent the animals 

 inoculated with them from contracting tuber- 

 culosis. In another series of experiments Dr. 

 Peserico kept the infected cigar-ends in damp 

 surroundings, and it was satisfactory to find that 

 under these conditions the tubercle bacillus at the 

 end of ten days was entirely deprived of its 

 virulence. Encouraged by these results, inocula- 

 tions were made with cigar -ends which had 

 been left in the open and exposed to normal 

 atmospheric conditions, which included falls of 

 rain and snow, and in this case also no symptoms 

 of tuberculosis followed their introduction into the 

 guinea-pigs. These experiments show that the 

 tubercle bacillus is prejudicially affected by con- 

 tact with tobacco when the latter is kept in a 

 moist condition, but that in a dry condition the 

 properties in tobacco inimical to its vitality are not 

 liberated and the bacillus can retain its virulent 

 properties for a period of over twenty days. 



In view of the importance of this discovery on 

 the destruction of the toxic character of the 

 tubercle bacillus by contact with moist tobacco, 

 further experiments were made in which emulsions 



