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power of resisting asphyxia. Dogs, cats, rabbits, guinea-pigs 

 and birds, are subject to the same law when they are adult as 

 when they are very young. The lower their temperature, the 

 longer they live when they are asphyxiated. But although the 

 existence of this law for adult vertebrata is beyond all doubt, it 

 is sometimes very difficult to ascertain that existence. It is not 

 easy to diminish the temperature of a non-hybernating adult 

 mammal, or that of a bird, without exhausting the nervous and 

 the muscular power of the animal, and also without producing a 

 general and considerable perturbation. The action of a cold 

 bath, for instance, so powerfully excites the vertebrata, that 

 sometimes violent convulsions take place, and then death may 

 occur in a short time, even before the animal has lost 10 cent. 

 (18 Fahr.) of its temperature. However, some individuals may 

 be cooled without being exhausted by convulsions. I have ex- 

 perimented on a great many which were in this condition. 

 For more than eight years, without intending to make experi- 

 ments on this subject, I have had the opportunity of stating, on 

 more than a hundred adult rabbits or guinea-pigs, used for other 

 researches, that, when their temperature is diminished, the dura- 

 tion of their life, when they are completely deprived of breathing, 

 is decidedly longer than in the normal state. Whatever has been 

 the cause of the cooling, the effect has been the same. In these 

 numerous experiments, the animal heat has been diminished, 

 either by a disease, by a poison, by an injury in the nervous 

 centres, by the immersion of the animal in melted ice, or by the 

 application of a layer of oil, essence, or gelatine, to the whole 

 skin of the animal. 



The best mode of cooling a non-hybernating warm-blooded 

 animal is to make the following experiment, in a room where the 

 temperature of the air is not far from freezing point. I remove 

 the superior part of the cranium of a mammal or of a bird, and 

 afterwards cut the brain, slice by slice, from the anterior to the 

 posterior extremity. After the ablation of the cerebrum and the 

 cerebellum, the animal is put on the floor, where it is left per- 

 fectly quiet for an hour or two. If the experiment is made on 

 a rabbit or a guinea-pig, the temperature of the animal then falls 

 from 40 Cent. (104 Fahr.) to 30 or 35 Cent. (86 or 95 F.) 



