﻿AN INVESTIGATION ON THE INFLUENCE UPON THE VITAL 



EESISTANCE OF ANIMALS TO THE MICRO-OEGANISMS 



OF DISEASE BROUGHT ABOUT BY PROLONGED 



SOJOURN IN AN IMPURE ATMOSPHERE. 



By D. H. BERGEY, M. D. 



This is a report of an investigation outlined by, and conducted under 

 the supervision of Drs. John S. Billings and S. Weir Mitchell, in which 

 an attempt has been made to determine whether impure atmosphere 

 produces detrimental influence upon the animal organism as shown in 

 greater susceptibility to certain diseases. 



Outline of the Investigation Peoposed by Dk. Billings. 



" The impurities to be tested are carbonic acid in the proportions of 

 0.5 to 2.0 per cent, by volume; ammonia and carbonate of ammonia in 

 the proportion of 0.1 to 1.0 per cent.; the products of respiration of 

 a series of animals arranged as in the Brown-Sequard experiments; and 

 the gases from offensive putrefying material. 



Afterward it may be desirable to test the effects of sulphuretted 

 hydrogen, and of the vapors of certain volatile organic compounds 

 having offensive odors (skatol, indol, mercaptan). 

 . The micro-organisms to be tested are those of anthrax, streptococcus, 

 diphtheria, tuberculosis, and of croupous pneumonia. 



The animals to be used are mice, rabbits, guinea-pigs, and later 

 monkeys. 



It is desirable that in each set of experiments the effects of high tem- 

 peratures (80°-95° F.) be compared with those of lower temperatures 

 (50°-60° F.). 



The animals to breathe these mixtures are to be placed in glass jars, 

 or bell-jars, and the inhalation of each mixture should continue for at 

 least one week before inoculations are made, and should continue for 

 a week after the inoculations." 



The expenses of this investigation were defrayed out of a grant 

 obtained from the Hodgkins Fund in the hands of the Smithsonian 

 Institution. 



