WHAT WE BREATHE 47 



of tobacco were infected with tuberculous sputum. 

 It was found that the bacilli steadily declined 

 in virulence as the length of time they were 

 kept in the emulsion was prolonged. Thus 

 whereas after a few hours they were still armed 

 with all their virulent properties, after three days, 

 out of the four animals inoculated with the 

 emulsion three succumbed to tuberculosis, after 

 five days two out of four succumbed, whilst after 

 eight days only one animal out of the four was 

 infected, and after a period of ten days' immersion 

 in the tobacco emulsion the tubercle bacillus failed 

 to kill a single animal. 



Cigar- and cigarette-ends were collected from the 

 streets and cafes of Padua by Peserico, but in spite 

 of consumption being stated to be very prevalent 

 in this city, in no single case could the presence of 

 the tubercle bacillus be discovered, although, as in 

 the other investigations, the surest method for its 

 detection, i.e. animal inoculations, was employed. 



Brief reference may be made also to the ex- 

 periments conducted to ascertain if cigars and 

 cigarettes, as sold, contain the tubercle bacillus. 

 The more interest attaches to this investigation 

 because it is well known that the operators em- 

 ployed in tobacco factories are, as a rule, an un- 

 healthy class, diseases of the respiratory organs, 

 and especially tuberculosis, being very prevalent 



