502 Effect of Exposure to Liquid Air upon B. Tuberculosis. 



Tubes. 



Treat- 

 ment. 



Animal 

 died or 

 killed. 



After 



Precis of post-mortem results. 



M. 



Alternate 

 exposure 

 aa above 

 to room 

 tempera- 

 ture and 

 extreme 

 cold 



killed 



100 days 



No evidence of tubercle found in animal 

 of English, series. In that of French 

 series a few minute tubercles were 

 found in lung structure. 



The control animals (inoculated from Tubes 0) died after a period 

 of 42, 54, 56, and 63 days, respectively, the autopsy of these showing 

 marked tuberculosis, affecting almost every organ of the body. The 

 series of animals, of which the autopsy was made at the Pasteur 

 Institute, gave results in every way corroborative of those detailed 

 above. 



It should be noted : 1. That the control animals succumbed to the 

 disease at a much earlier date than those inoculated with the exposed 

 material, seven of these latter being still living on the 100th day from 

 the commencement of the experiment. The sole exception to this is 

 guinea-pig 13 G, inoculated with material exposed for one week, which 

 died on the thirty-third day. 



2. That the time of exposure appeared to make no difference, the 

 animals inoculated with material exposed for forty- two days showing 

 at death tuberculous lesions as pronounced as those in which the 

 material was exposed for the shortest period. 



3. That no difference could be traced in the virulence of the 

 material exposed to contact with liquid air. 



4. That in animals inoculated with material which had been 

 subjected to alternate exposures, it was difficult to find evidence of 

 tubercle. It was only after very careful search that some small 

 tuberculous lesions could be discovered. 



To sum up the results of the experiment, it would appear then — 



1. That simple exposure to the temperature of liquid air has little 

 or no effect upon the bacillus tuberculosis as far as vitality is 

 concerned. 



2. That its virulence is to some degree modified, but not destroyed, 

 by such exposure, even if it be continued for a lengthened period. 



3. That length of exposure is not a factor in the question. 



4. That actual immersion in liquid air has no special effect upon 

 the organism, nor does it produce results in any way differing from 

 simple exposure to the temperature obtained by it. 



5. That successive alternations of extreme cold and normal tern- 



