924 Experiments 



form, and which have mistakenly been named the "period of exci- 

 tation." And besides we might very probably avoid them by 

 lessening the speed of the elimination of the carbonic acid. 



But while I call attention of the surgeons to this anesthetic, 

 which has often been considered but which has never been studied 

 with sufficient care, I am far from believing that the preceding 

 researches are precise and detailed enough to authorize immediate 

 application: an experimental table upon which a dog is fastened 

 is one thing, and the bed of a patient is another. 



While trying to give myself a precise idea of the inner action 

 of carbonic acid, I reach the following considerations: 



The excretion of the carbonic acid which is constantly being 

 formed in the interior of the tissues is a necessary condition on 

 account of the continued metabolic exchanges which give rise to it. 

 Here, as in so many other chemical phenomena, the product of the 

 reaction must be eliminated constantly so that this reaction may 

 maintain its maximum activity. When, through respiration in 

 closed vessels, under conditions specified above, the carbonic acid 

 is stored up in the tissues, it delays all the oxidations there, as is 

 proved by the rapid drop in the temperature. As for the nervous 

 system, if it seems affected first, that is because it is the first to 

 show the general effects which disturb the whole organism; and 

 because the spinal cord fails in its reflex functions of sensitivity 

 and respiration, just as it is the first to show the organic disturbances 

 which occur when we bleed, diminish or increase the 2 of the 

 blood, chill, or overheat an animal. 



But when the carbonic acid is artificially brought from outside, 

 and when it is inhaled in a gaseous mixture, it is not the whole 

 organism which is affected as in the first case. The carbonic acid, 

 absorbed by the arterial blood in passing through the lungs, is 

 immediately carried by it to the nervous center, the metabolic 

 changes of which are therefore suddenly disturbed, delayed, and 

 altered: hence the anesthesia. Finally, when the proportion is 

 great enough in the respiratory mixture, the cardiac ganglia them- 

 selves are immediately affected in their metabolism and the heart 

 stops, paralyzed. 



5. Action of Carbonic Acid upon the Lower Living Beings. 



The universality of action of carbonic acid upon all tissues is 

 shown very clearly when we experiment upon lower animals. Long 

 ago, for example, I showed in my courses that frogs or new-born 

 mammals die sooner in carbonic acid than in carbon monoxide. 



