iQii] Charles A. Doremus 253 



dioxide is used, the moist carbon dioxide from the lungs decom- 

 poses this Compound, forming sodium carbonate, and releasing 

 oxygen. Accidents to submarine boats are guarded against by the 

 use of this Compound. 



The isolation of oxygen from the air, according to Tessie du 

 Motay's process, was being conducted on a commercial scale. The 

 20,000 cubic foot holder suppHed the gas to those who would take 

 the trouble to visit the works and obtain permission to inhale the 

 gas. Compressed in cyHnders it was sent to the homes of patients 

 and allowed to escape freely into the sick room. Great rehef was 

 found by those suffering from asthma, pneumonia, diphtheria, and 

 other diseases, and unfortunately at no time since has oxygen been 

 as easily at the command of the physician. It is to be hoped that 

 the great demand feit in the commercial world for cheap oxygen 

 will soon result in the development of some process to put it again at 

 the command of all. 



When the first Brooklyn Bridge was built a caisson was sunk 

 on the New York side and on it the pier which carries the cables 

 was erected. The work had to be done below the surface of the 

 river and in compressed air. Never before had there been an 

 opportunity to study so thoroughly the effects of compressed air on 

 respiration. The gangs of workmen were put under scientific Obser- 

 vation and control. Dr. Andrew H. Smith, after long study of the 

 conditions and of the illness from which the men suffered, gave the 

 name of " caisson disease "^ to the serious, often fatal, character of 

 the Symptoms which developed after the men emerged from the 

 compressed air. The rules he formulated have since been employed 

 to Protect the men while performing such dangerous tasks, now 

 frequently occasioned by tunneling under rivers, or laying founda- 

 tions. 



When the highly improved respiration calorimeter was built 

 at Middletown, Conn., and investigations with it were made by 

 Atwater and his corps of assistants, the study of the metabolism of 

 the human body at rest, at work of various kinds, and under the 

 use of different foods, yielded a vast amount of Information. 



^ " The Effects of High Atmospheric Pressure, Including Caisson Disease," 

 by Andrew H. Smith, M.D., 1873. Prize Essay of the Alumni Association of 

 the College of Physicians and Surgeons, N. Y. 



