1894.] Influence of certain Agents on the Tubercle-Bacillus. 51 



paper. The full load capacity of the transformer was about 6,000 

 watts. The range of frequency (including the autographic recorder, 

 the wattmeter and the Joubert's instantaneous contact method experi- 

 ments) was about from 3 per minute to 8,000 per minute. The results 

 indicated that, throughout this range, there is no variation in the 

 dissipation of energy per cycle when, the inductions are equal. 



Data deduced from these experiments as to the magnetic qualities 

 of the iron used in the different transformers are given in the paper. 



V. " On the Influence of certain Natural Agents on the Viru- 

 lence of the Tubercle-Bacillus." By AUTHUR RANSOME, 

 M.D., F.R.S., and SHERIDAN DEL^PINE. Received May 1, 

 1894. 



Three years ago Dr. Ransome communicated to the Society the 

 results of some experiments, carried out in concert with Professor 

 Dreschfeld, of Owens College, " On certain conditions that modify 

 the virulence of the bacillus of tubercle." 



The tendency of these researches was to prove " that fresh air and 

 light, and a dry and sandy sub-soil, have a distinct influence in 

 arresting the virulence of the tubercle-bacillus ; that darkness some- 

 what interferes with this disinfectant action ; but that mere exposure 

 to light, in otherwise bad sanitary conditions, does not destroy the 

 virus." 



The following table gives the results of similar experiments by 

 ourselves. 



Experi- 

 ment 

 No. 



3. 1. 



7. 2. 



8. 3. 



11. 4. 



12. 5. 



58. 6. 



59. 7. 



Table I. 



Rabbit inoculated in peritoneum with fresh sputum. Killed 55 days 



after. Showed well-marked tuberculosis. 

 Rabbit. Sputum exposed to light and air 45 days in June and July. 



Showed no tuberculosis after 86 days. 

 Rabbit. Sputum exposed in air-shaft in dusk at the same time. 



Showed slight tuberculosis after 86 days. 

 Guinea-pig. The same sputum exposed at the same time, in air and 



light, inoculated under the skin. Showed no distinct tubercle 



in 80 days. 



Guinea-pig. Same methods, only in dusk. Showed advanced tuber- 

 culosis in 80 days. 

 Guinea-pig. Another sputum exposed in April for 16 days to little or 



no air, in darkness. Gave well-marked tubercle after 42 



days. 

 Guinea-pig. Ditto, ditto. 



E 2 



