EFFECTS OF HEAT ON THE ANIMAL ECONOMY. 



2U 



Mr. Dclaroche made a great number of experiments too Heat applied 

 on the heat both men and animals are capable sf enduring in mva ' 

 baths of hot water, and in vapour baths ; on the inliuonce 

 heat exerts on respiration ; on the connexion that exists be- 

 tween the evaporation of the perspirable matter and i;;o fa- 

 culty animals possess of producing cold; on the influence v 

 of heat on respiration ; and on the state of the bodies of 

 animals destroyed by excess of heat. 



He concludes his labours with the following observations. 



Such are the inquiries I have made, with a view to inves- The subject not 

 tigate the effects of a strong heat on men and animals. I exhausted. 

 could have wished to have extended them farther, and ren- 

 dered them more complete: but the time such a labour 

 would have required, and the difficulty attending it, did not 

 permit me. I cannot therefore deduce from them general, 

 consequences, but I shall briefly recapitulate the results General results. 

 they afforded me. 



1. The object of my first experiments was to determine Small animals 

 the degree of heat requisite to destroy animals; and from 1 l^™^ *l^ en 

 them I learned, that small animals perished on exposure toatlSS 9 25. 



a heat of 144° -5, or even of 133° '25. It is even proba- 

 ble, that a lower heat, but longer continued, would pro- 

 duce this effect. 



2. Mr. Berger and I confirmed by experiments made on Extent of the" 



ourselves, the faculty that man possesses of enduring expo- f apacUy , ° t suS ' 



' J r ... tainit, g heat 



sure to high temperatures, though but for a short time it is differs. 



true. A comparison of these experiments with each other, 

 and with those of Sir Charles Blagden, taught us, that the 

 extent of this faculty might be very different m different in- 

 dividuals. 



I. The experiments in which we exposed ourselves to the Dry heat borne 

 action of aqueous vapour enabled us to verify an observation most easily. 

 of Dr. Fordyce, that the sensation of air loaded with va- 

 pour is much more painful than that of dry air at an equal 

 temperature. 



4. We endeavoured to calculate with precision by weigh- Perspiration in 

 ing the effects of heat on perspiration. The loss of weight t e m p a eralU re. 

 we experienced in this way appeared to be in the direct ratio 

 of the increase of temperature. We found too, that the 

 heat of aqueous vapour excited perspiration much more 

 powerfully than dry heat. 5. I 



Vol. XVII. July, 1807. Q 



