1()12\ F.V1K OF Tl'liKKCLK BACILLI OUTSIDIi THE ANIMAL BODY 295 



TABI,E 3 ACTION OF DIFFUSE L,IGHT UPON TUBERCLE BACILLI 



EFFECT OF DESICCATION UPON TUBERCLE BACILLI IN SPUTUM 

 AND OTHER MATERIAL 



The difference in the length of time that different bacteria 

 withstand desiccation is very great. B. cartovoms is killed in a 

 few minutes to a few hours (Jones 64 ) ; B. tuberculosis may be 

 killed in a few days ( 14 days, Maffucci 90 ) to several days (88 days, 

 Rickards 119 ); and spores of Bact. anthracis live twelve years 

 (reported above). 



The difference depends upon the kind of substance on which 

 they are exposed and upon the difference in the kind and form of 

 organism exposed. Harding and Prucha 54 have shown that Bact. 

 campcstrc remains alive much longer when dried on cabbage seed 

 than when dried on glass covers ; on glass it was dead at the end 

 of ten days; on the seed it remained alive for thirteen months. 

 This difference is no doubt largely due to the difference in the 

 hygroscopic moisture retained by these substances. The kind and 

 form of the organism exposed to drying has even more to do with 

 its capability of living. The spore form lives very much longer 

 than the vegetative form. 



