542 THE POPULAR SCIENCE MONTHLY. 



within live minutes, and the cat not only continued to breathe, in 

 profoundest sleep, for forty-five minutes, but would have been recov- 

 erable by simple removal from the vapor into fresh air if it had been 

 removed while yet one act of breathing continued. This, however, 

 was exceptional, because the cat in the same lethal atmosphere as the 

 dog does not, as a rule, live more than thrice as long ; i. e., if the dog 

 ceases to breathe in four minutes, the cat will cease in from ten to 

 twelve minutes after falling asleep. 



The character of the vapor used does not make any difference, 

 relatively. Carbonic oxide, carbonic acid, chloroform-vapor, carbon- 

 bisulphide vapoi', yield the same relative results. Pure carbonic oxide 

 kills with intense rapidity, but it kills the cat less quickly than the 

 dog. If instead of a lethal vapor prussic acid be used, in administra- 

 tion by the mouth, the cat dies more slowly than the dog. The same 

 is true in respect to death by drowning. 



Still more curiously, recovery from apparent death is much more 

 frequent in the cat than in other domestic animals. Mr. Warrington 

 once observed a cat recover from apparent absolute death by prussic 

 acid, eight hours after it had lain as if dead. I once saw a young cat 

 come back to life after two hours of immersion under cold w r ater. 



I do not know many facts bearing on tenacity of life in other ani- 

 mals, but I have observed that sheep in a lethal atmosphere die very 

 rapidly, goats much less rapidly, and pigeons more rapidly than com- 

 mon fowls. There is, apparently, a specific tenacity in all species. 



In animals of the same species there are distinctions determinable 

 by peculiarities in the animal itself. In one instance where a large 

 number of dogs were put to sleep in the lethal chamber, one was 

 found in deepest sleep, but still breathing, side by side and partly 

 covered by another that was not only dead but cold and rigid. A 

 similar fact occurred last year in the human subject in a mine. A 

 father and son killed by fire-damp lay together, the father dead, the 

 son living, though he, the son, had come first under the influence of 

 the lethal gas. In all the fatal accidents to the human subject from 

 the administration of chloroform or other narcotic vapor we see the 

 same illustration. I doubt whether in any one of these unhappy 

 events the death has been induced by what would be, under the com- 

 mon run of administrations, a fatal dose. But some die from a dose 

 that would not so much as narcotize others. An analogous series of 

 facts is met with in relation to the effects of physical and mental 

 shocks and to surgical operations. 



The variation of measure of tenacity of life is unquestionable. 

 What is the reason of it ? What is there in one species of animal 

 that gives a measure of tenacity over another ? Why, for instance, is 

 the cat more tenacious of life than the do<j ? 



The only answer as yet is, that the cat is endowed with more vital- 

 ity. But this is no answer as to details. Is the endowment of the 



