THE 



PHILOSOPHICAL MAGAZINE. 



L Researches respecting the Action exercised by Caloric on 

 the Vitality of Animals. By Victor Michelotti, * 

 M.D.* 



JL he necessity of caloric for the maintenance of life has 

 at all times been acknowledged f : in consequence of the in- 

 genious experiments of Haller on irritability, which showed 

 with what facility caloric excites the irritable parts of ani- 

 mals, a very eminent exciting property has been ascribed 

 to it. 



If the motion of the irritable parts increases in the ratio 

 of the degree or of the dose of the irritants applied, every 

 other circumstance being equal, it is no less certain that 

 by heating the irritable parts their motion is increased. It 

 has also been found that the application of caloric to excite 

 an animal or an irritable part ought only to be made by de- 

 grees, especially if the living being is in a state of torpor ; 

 which agrees with what has been observed in regard to cer- 

 tain known excitants ; for to bring by their means a living 

 being to a state of less excitement it is necessary to proceed 

 only by degrees in removing the excitants. But caloric in 

 this respect presents one difficulty to be resolved. 



* From the Journal de Physique, Brumaire, an. 12. 



f What Cicero says in his sublime work De Natura Deorum, is very 

 remarkable : — Sic enim res se ftabet, ut omnia quse alantur et quae cres- 

 *cant, contineant in se vim caloris, sine qua nee ali possent nee crescere; 

 nam omne quod est calidum et igneum cietur et agitur motu suoj quod 

 autem alitur et crescit, motu quodam utitur certo et aequabili ; qui quam- 

 diu remanet in nobis, tamdiu sensus et vita remanet; rcfrigerato autem et 

 exrincto calore. occidimus ipsi et extinguimur .... Jam vero venae et 

 tfrterise m'icare non desinunt, quasi quodam igneo motu ; animadversumque 

 saepe est cum cor animantis alicujus evulsum ita mobiliter palpitaret ut 

 imitaretur igneam celeritatem. Omne igitur quod vivit sive^animal sive 

 *erra edituin, id vivit propter inclusum in eo calorem. Etc**-lib. ii. 9. 



VolIXIX. No. 73. A 2 The 



June 1304. 



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