742 Experiments 



lessens in the intervals, and finally all symptoms disappear at the 

 end of a few minutes or, at the most, a few hours. 



In lighter cases, instead of attacks so violent that one can lift 

 the animal by a single foot, stiff as a piece of wood, as Figure 61 

 shows, we observe irregular movements, local convulsions, symp- 

 toms, in a word, which are much like those of poisoning by phenol. 

 We sometimes see acts which seem to indicate a certain mental dis- 

 turbance. 



In very serious cases, on the contrary, the stiffness is continual, 

 with a few clonic increases from time to time; the teeth grind 

 and clench so as to appear nearly ready to break, and death may 

 occur after one or two attacks, separated by a few minutes. We 

 then find the blood red, even in the portal system; then it turns 

 dark. When the animal no longer makes any movement, the heart 

 still continues to beat for a few minutes. At other times, as in 

 Experiments CCLXXVIII and CCXCVII, the convulsions last 

 nearly 24 hours before ending in death. 



We find no congestions or ecchymoses in the lungs and the 

 nervous centers. Only consistently in sparrows, we see the cranial 

 diploe filled with a hemorrhage in dots, in smaller or larger spots, 

 or even in a sheet covering the occipital region, and, in the most 

 violent cases, the whole extent of the cranium. These bloody 

 suffusions, the cause of which does not seem to me easy to explain, 

 are invariably present in oxygen poisoning. They appear some 

 time before the moment of death. But they are not peculiar to 

 this kind of death, and in the preceding experiments we find them 

 noted, even in simple asphyxia, under diminution of pressure (See 

 Experiments CCLII and CCLIII). 



The appearance of the symptoms which we have just described 

 seems to indicate that the toxic action produces its effect on the 

 nervous centers, as do strychnine, phenol, and other poisons which 

 cause convulsions. This conjecture is corroborated by the fact 

 that inhalations of chloroform stop the convulsions momentarily, 

 although they reappear when the anesthesia has worn off. Let us 

 remember that, according to our experiments on frogs, if the 

 sciatic nerve has been cut in the hind leg, there are no convulsions 

 in the muscles animated by this nerve. 



To summarize all these facts, I shall quote here the con- 

 clusions of the report which I had the honor to make on this subject 

 to the Academy of Sciences, February 17, 1873. 



