190 



of his body possesses the ordinary degree of sensibility, may be destroyed 

 by the protracted application of caustic substances, and would be con- 

 sumed by fire, if applied for a sufficient length of time, and nitric acid 

 would infallibly destroy his tongue, if he took any into his mouth, as it 

 has been said he did. This man, therefore, in no one respect departs 

 from the known laws of the animal economy, but, on the contrary, affords 

 an additional proof of the influence of habit on our organs. 



LXXXI. Before bringing to a conclusion this article on animal heat, 

 it remains for me to explain how the body resists cold, and preserves its 

 temperature, in the midst of a frozen atmosphere. This cannot be ac- 

 complished without an increase of activity in the organs, it is only by 

 augmenting the sum of the combinations by which caloric is disengaged, 

 that we can succeed in making up for the loss of that principle, so ne- 

 cessary to our existence. What is the reason that in cold weather di- 

 gestion is more active, (Hieme vero ventres aunt calidiores, Hipp.) the pulse 

 stronger and more frequent, and the vital energy greater? It is because 

 heat comes from the same source, and is produced by the same mechanism 

 as the nutrition of the organs; and that its evolution may go on increasing, 

 it is necessary that the secretions, nutrition, in a word all the vital func- 

 tions, should increase in the same proportion. 



Observe, for a moment, a man who is exposed to a moderate degree of 

 cold, he feels more activity, more strength, and is more nimble, he walks 

 and exerts himself, the most violent exertions do not appear to him, labo- 

 rious, he struggles against the disadvantages of the debilitating influence; 

 and provided the cold is not excessive, and the body tolerably vigorous, 

 there is disengaged, within himself, a sufficient quantity of caloric to 

 makeup for the loss of that which is carried off by the air and the surround- 

 ing bodies. These general effects of cold are not disproved by what hap- 

 pens, when only a part of the body is exposed to it. Supposing the tem- 

 perature a few degrees below zero, there is felt, at first, a sensation of 

 cold much more inconvenient, caeteris paribus, than if it acted on a more 

 extensive surface. The spot on which the cold air acts, becomes affect- 

 ed with a painful sense of pricking, reddens, then inflames ; and in this 

 case, inflammation is evidently the result of a salutary effort ef nature 

 \vhich determines into the inflamed part, an excess of the vital princi- 

 ple*, so that the quantity of heat that is disengaged may correspond to 

 that which has been abstracted. The effort of this conservatory principle, is 

 more marked, than if the whole surface of the body were^at once exposed 

 to cold, because, acting wholly on a limited point, of small extent; it 

 operates with more intensity. 



Beyond a certain degree, however, nature in vain struggles against 

 cold; if severe, and if the creature exposed to it, have not the power of 

 sufficient re-action, the part becomes purple and benumed from the loss 

 of its caloric, vitality ceases, and it mortifies ; and if the whole body is 

 equally exposed to the influence of cold, the person is benumed, feels a 

 stiffening of his limbs, stammers, and overpowered by an irresistiWe pro- 

 pensity, yields to a sleep which inevitably ends in death. By yielding 

 thus to the illusive sweets of a perfidious sleep, many travellers have pe- 



* This pathology is incorrect. The part reddens and inflames, because its life has 

 been impaired and it is no longer able to bear the impulse given to the blood by the 

 heart. Hence it becomes engorged with blood, or in other words diseased. Godman. 



