Theories and Experiments 473 



increase in the quantity of carbonic acid; and analyses made before 

 the beginning of my series of compressed air treatments would cer- 

 tainly have given a production of carbonic acid corresponding 

 perfectly with that of the authors, that is, a smaller quantity. 



The result then establishes indubitably as a -fact that the direct 

 effect of the compression of the air as well as the delayed effect of a 

 daily two-hour treatment in compressed air, repeated for a certain 

 time, produces a greater exhalation of carbonic acid, and consequently 

 also an increase in the quantity of oxygen absorbed. 



From this increase in the quantity of oxygen absorbed, which 

 Vivenot considers proved, he draws general conclusions of the 

 greatest importance: 



Two facts which agree perfectly with what precedes are: 



1. The greater need of nourishment which is shown as an effect 

 of the compressed air by a noticeable increase of appetite, which I 

 noted in myself and in others, and which is observed especially and 

 without exception in laborers working in compressed air; 2. the very 

 considerable increase in the urinary secretion, observed again in my- 

 self during this series of experiments and in several other persons, 

 and evidenced especially in the first treatments with compressed air. 



Therefore there is produced in the body a greater exchange of 

 materials, and that also explains apparently contradictory results, 

 observed by different authors. 



There is an increase in the weight of the body, noted by several 

 authors as a result of the stay in compressed air: for instance, J. Lange 

 (of Utersen), who says he observed a weight increase of 5 kilograms 

 in thirty-eight days (from 58 to 63 kilograms) in one person, and of 

 5 kilograms in 21 days in another. I can confirm this observation by 

 what I noted in myself; for my weight had increased in four months 

 (from April 30 to September 1) 3% pounds (from 127.5 to 130 pounds), 

 which is all the more conclusive because it was in the middle of the 

 warm season when, as is well known, the weight of the body usually 

 decreases. 



But on the other hand, there is one fact which cannot be disputed 

 either, and that is the considerable decrease in weight of laborers 

 working under a pressure of three to four atmospheres (in coal mines 

 or in the construction of bridges). Sandahl has observed the same 

 fact as a result of the therapeutic use of compressed air, so that this 

 treatment has already been advised rather frequently as a means of 

 combating obesity. 



The apparent contradiction of these effects resulting from the 

 increase of the air pressure, is explained by considering the connection 

 between the need, the supply of materials, and the combustion. The 

 need of increased nourishment is felt. If then the increase in appetite 

 and the possibility of getting more food can not only counterbalance 

 but even exceed the increased combustion of the materials of the 

 blood (which will be the case with only a slight increase in pressure 

 and relatively short daily treatments), an increase in the body weight 

 will necessarily result. But if in the case of a combustion of carbon 



