i On the Action exercised hj Calorie 



The experiments of the celebrated Hunter are well known. 

 1 By these he found that several living beings are more injured 

 by a successive and slow passage to cold than by a rapid 

 change of temperature. It is known that Hewson observed 

 that blood rapidly frozen still possesses the property of coa- 

 gulating, which never takes place if it has been frozen 

 slowly. It is certain that the arguments of Hunter for a 

 certain vitality in the blood, deserve the attention of phy- 

 siologists. 



M. Dufay* and the celebrated Blumenbachf have had 

 occasion to observe that salamanders and frogs speedily 

 frozen are preserved alive in the midst of ice, for they* 

 may be brought to life by exposing them slowly to heat.. 

 Besides, it is a fact well known that the men in several of 

 the northern nations, after they have heated themselves 

 thoroughly, immediately plunge into cold water, or even 

 mto snow, without any inconvenience J. 



Whatever method may be taken to explain this pheno- 

 menon, it appears to me that it must always be admitted 

 that a sudden passage to cold can be followed only by a 

 privation of caloric greater and more rapid, according as the 

 two temperatures to which the bodies are successively ex- 

 posed are more distant, that is to say, when there is always 

 a sudden removal of an excitant. 



Since the action of caloric does not here correspond with 

 what has been observed in regard to other excitants, the re- 

 moval of which is the more dangerous to animals the spee- 

 dier it is, it will be necessary to seek for the cause in the 

 action itself Which caloric exercises on living beings. But 

 before we deduce from these facts the consequences which 

 might overturn the opinion commonly entertained of the 

 action of caloric, and which seems to be supported by a 

 great number of experiments, I think it necessary to make 

 better known, and more directly, what takes place to ani- 

 mals deprived slowly or rapidly of the caloric necessary for 

 the state of life. 



The object here in view will be only the caloric necessary 

 for the state of life, and not that which is necessary for an 

 organized being to retain its vitality, as it may be in the 

 latter state, without being what is called alive. 



To ascertain what would happen to animals during a 

 slow transition to cold, it appeared to me at first that in- 



* Mem. de I'Acad. des Sciences de Paris 17x9, p. 135. 

 f Biumenbachii Specimen Physiologiae Comparatae, &c. j Gottingse 

 1787, p. 10. 

 X Coxe's Travel 3. 



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