578 Experiments 



Subchapter III 

 SUMMARY AND CONCLUSIONS 



Summarizing, if we clear the principal results from the inci- 

 dental questions which we have brought up and settled in the 

 course of our research, the study of death in confined air under 

 different pressures brings us to the following formulae. 



In ordinary air: 



A. — At pressures lower than one atmosphere, the death of ani- 

 mals occurs when the oxygen tension of the air is reduced to a 

 certain constant value (which for sparrows equals on the average 

 O, xP = 3.6). 



B. — For pressures included between 2 and 9 atmospheres, death 

 occurs when the carbonic acid tension rises to a certain constant 

 value (which for sparrows equals on the average CO, x P = 26) . 



C. — For very high pressures, death is due exclusively to the too 

 great tension of the ambient oxygen. It comes quickly when the 

 tension of this gas reaches 300 or 400. 



D. — For pressures of 1 to 2 atmospheres, death seems to be due 

 especially to the lowering of the oxygen tension, but in part also to 

 the rise of the C0 2 tension. 



E. — Starting with 3 or 4 atmospheres, the fatal effect of the 

 oxygen begins to be felt, and becomes very evident at about 9 or 

 10 atmospheres. 



Experiments made either with gaseous mixtures more or less 

 rich in oxygen, or in the presence of alkalis capable of absorbing 

 the carbonic acid as it is formed, cause us to give to these laws an 

 even greater character of generality, and we can formulate them in 

 the following manner (applying them, for greater clearness, to 

 sparrows) : 



The tension of a gas being represented by the product of its 

 percentage multiplied by the barometric pressures, we see that 

 death occurs: 



A. — When the oxygen tension drops below 3.6, whether the 

 barometric pressure is above or below the normal pressure; of 

 course, in the first case, the carbonic acid must be removed by an 

 alkali. 



B. — When the carbonic acid tension rises above 26, whether the 

 pressure is above or below the normal pressure; of course, in the 

 latter case superoxygenated mixtures must be used. 



