on the Vitality of Animals. g 



animals, ought not to vary much in its manner of acting 

 on others. 



In making experiments on ants, spiders, frogs, 8cc, I 

 have found, 



1st, That I may consider as highly applicable to my ani- 

 mals what was observed by Hunter and Hewson in other 

 vital beings, such as pullets' eggs, anu twn blood, which 

 one might suppose to have no relation to living beings if 

 this grand and universal principle, which communicates life 

 to all organic beings did not give, even in the blood, signs 

 of its existence. 



2d, By inquiring directly what would take place in dif- 

 ferent temperatures, I have sufficiently proved, in my opi- 

 nion, that we must not seek for the reason of the preserva- 

 tion of life during sudden transitions from one temperature 

 to another, but in the speedy privation of caloric. 



To explain the phenomena here related, I find myself 

 obliged to recur to three hypotheses, and to consider caloric 

 first as a particular excitant. 



1st, It seems to me that we must admit that the slow 

 privation of caloric produces a greater debility than rapid 

 privation. It is well known that an animal when kept 

 very warm, well clothed, &c, may resist more the debili- 

 tating causes ; but it is true that in this case the animal 

 contains a greater quantity of excitants, and for a similar 

 reason a greater degree of excitability ought to be ascribed to 

 oxygenated animals *. Is it therefore a greater or less loss of 

 the exciting caloric that deprives animals of life or preserves 

 it ? But then it is seen that animals exposed to cold and at 

 equal temperatures during a considerable time, ought to have 

 lost only that quantity of caloric which is indicated by the 

 temperature, yet so great is the difference between them. 



2d, If caloric be considered only as a modification of 

 matter, a kind of motion for example, I can the less con- 

 ceive that the animal should be colder. But how are ani- 

 mals preserved in life by losing in a speedier manner this 

 kind of movement ? It is because the organic parts, by the 

 help of a slow change, assume dispositions which they 

 could not acquire by a sudden privation. 



3d, A similar explanation may be given if we consider 

 caloric as a matter which disposes living beings to motion 

 and sensation. 



* I shall make some observations hereafter on these facts, which have 

 been treated in an able manner by Dr. Beddocs and M. Socquet. 



II. History 



