EEPOET OF THE SECRETARY. 15 



Immediately after the announcement of the award of the first prize 

 to Lord Rayleighand Professor Ramsay, of London, for their discovery 

 of "argon," an element of the atmosphere, a draft for $10,000 was 

 despatched to these gentlemen, through the courtesy of the Department 

 of State, and of the Hon. Thomas F. Bayard, United States ambassador 

 to Great Britain. 



With regard to other work carried on by the Hodgkins fund, I may 

 state that Dr. J. S. Billings and Dr. S. Weir Mitchell have completed 

 the investigations begun by them in 1893, under a grant from the 

 Hodgkins fund, to determine the nature of the peculiar substances of 

 organic origin contained in the air expired by human beings, and their 

 report is now in press. 



In their report the investigators state that for a number of years 

 prior to 1888 the prevailing view among physicians and sanitarians 

 had been that the discomfort and dangers to health and life which had 

 been known to exist, sometimes at least, in unventilated rooms occu- 

 pied by a number of human beings were largely or entirely due to 

 peculiar organic matters contained in air expired by these persons, and 

 that the increase in carbonic acid due to respiration had but little effect 

 in producing these results, its chief importance being that it furnished 

 a convenient means of determining the amount of vitiation of the air. 

 Recently, however, several experimenters have concluded that the 

 organic matters in the exhaled breath are not harmful, at all events to 

 animals, and the main object of the investigations was to determine 

 the correctness of these conclusions. 



The investigators found that the air in inhabited rooms, such as the 

 hospital ward in which experiments were made, is contaminated from 

 many sources besides the expired air of the occupants, and that the 

 most important of these contaminations are in the form of minute par- 

 ticles or dust, in which there are micro-organisms, including some 

 of the bacteria which produce inflammation and suppuration. It is 

 probable that these dust particles were the only really dangerous ele- 

 ments in the air, and it appears improbable that there is any peculiar 

 volatile poisonous matter in the air expired by healthy men and ani- 

 mals other than carbonic acid. 



In concluding their report the authors state that the results of the 

 investigations, taken in connection with the results of other researches 

 summarized in the report, indicate that some of the theories upon which 

 modern systems of ventilation are based are either without foundation 

 or doubtful, and that the problem of securing comfort and health in 

 inhabited rooms requires the consideration of the best methods of pre- 

 venting or disposing of dusts of various kinds, of properly regulating 

 temperature and moisture, and of preventing the entrance of poisonous 

 gases like carbonic oxide derived from heating and lighting apparatus, 

 rather than upon simply diluting the air to a certain standard of pro- 

 portion of carbonic acid present. 



