REPORT OF THE SECRETARY. 11 



pherie air, and for essays on the air in relation to human life and 

 health, resulted in the award of the first prize of $10,000 to Lord Ray- 

 leigh and Prof. William Ramsay for their discovery of argon, a new 

 element of the atmosphere. The prize of $1,000 for the best popular 

 essay was awarded to Dr. Henry de Varigny, of Paris, for his essay 

 on "Air and life." 



Six of die papers submitted in competition for the prizes were 

 awarded honorable mention, together with medals, as announced in 

 my last report. The design for the medal is by M. J. 0. Chaplain, of 

 Paris, a member of the French Academy and one of the most eminent 

 medalists of the world. The obverse bears a female figure carrying a 

 torch in her left hand and in her right a scroll, emblematic of Knowl- 

 edge, and the words u Per orbem." The reverse is adapted from the 

 seal of the Institution, designed by St. Gaud ens, the map of the world 

 being replaced by the words " Hodgkins medal," as is shown in the 

 accompanying illustrations, which are the size of the original. The 

 medals were struck at the Paris mint. 



Dr. J. S. Billings and Dr. S. Weir Mitchell having completed their 

 investigations on the composition of expired air and its effects on animal 

 life, their report has been published as a Memoir of the Contributions 

 to Knowledge. The investigators found that the air in inhabited rooms, 

 such as the hospital ward in which experiments were made, is contam- 

 inated from many sources besides the expired air of the occupants, and 

 that the most important of these contaminations are in the form of 

 minute particles or dusts, in which there are micro-organisms, including 

 some of the bacteria which produce inflammatory and suppurative dis- 

 orders. It is probable that these dust particles are the only really 

 dangerous elements in the air, and the important conclusion is reached 

 that it appears improbable that there is any peculiar volatile poisonous 

 matter in the air expired by healthy men and animals other than car- 

 bonic acid. 



An additional grant has been made to Drs. Billings and Mitchell to 

 continue other lines of investigation, especially whether the long- 

 continued breathing of air rendered impure by respiration or by 

 volatile exhalations from the skin and mucous membranes increases 

 the susceptibility to infection by certain micro-organisms, especially 

 those which are now considered to be the specific causes of consump- 

 tion and croupous pneumonia, the diseases which are most fatal in 

 crowded and ill-ventilated rooms. 



THE AVERY FUND. 



The property devised to the Institution by the late Robert Stanton 

 Avery, of Washington City, consists of lots on Capitol Hill, some 

 improved by dwelling houses, and certain personal property, chiefly 

 represented by securities of the Northern Pacific Railroad Company. 



The real estate is of an assessed District valuation of $28,931, aud 

 the personal property, at its present market quotation, and after 



