10 Effects of Oxygen and other Gases 



offers no explanation of this result. He imagined that less 

 oxygen was consumed than when common air is breathed. 

 Can the difference of opinion upon this point arise from the 

 animals, being saturated with oxygen, returning it back again 

 unaltered ? The state of the gas, after every experiment, 

 seems to favour this question. Whether it be so or not, my 

 experience tends to subvert the conclusion of this author, which 

 is — that the fatal effects are independent of excess of oxygen, 



Messrs. Allen and Pepys found — that more of oxygen was 

 consumed) than is sufficient for the production of carbon. They 

 also observed that the blood gave off a corresponding quantity 

 of nitrogen ; and that the diminution of the volume of air was 

 found to be greater in pure oxygen than in ordinary respiration. 

 My experiments, in general, appeared to corroborate these 

 observations. 



The experience of M. Magendie shows the respiration of 

 pure oxygen to be fatal to animal life, and to exhibit a similar 

 tendency when the gas is mixed in proportions differing from 

 those of the atmosphere. This opinion seems to prevail in 

 France ; and it is expressed, alsOj by the valued testimony of 

 Dr. Prout. All the facts which we possess are decidedly in 

 favour of this opinion, as far as I can judge of them. 



Without quoting particular authorities any farther, I find it 

 is generally observable that some circumstances of a physiolo- 

 gical nature have been apparently overlooked in trying the 

 effects of oxygen upon the animal functions ; while the chemical 

 phenomena have been more fully investigated, and especially 

 by the recent researches of Messrs. Allen and Pepys, leaving no 

 points, perhaps, upon this ground incompletely treated. From 

 the constancy of the most important facts in my experiments, I 

 am inclined to think that I am justified in believing many of the 

 results, arrived at by others, to be unsatisfactory hitherto ; and 

 their occasional apparent contradiction of each other strengthens 

 this notion. 



We may refer to the invariable manner in which animals, 

 after remaining some time unaffected by breathing pure oxygen, 

 begin to be excited, and their respiration and sanguineous cir- 

 culation become greatly increased ; and to the gradual state of 

 debility and subsequent insensibility following, with loss of 

 voluntary motion, and the cessation of the diaphragm's con- 



