544 



REPORT — 1902. 



towards answering it, he describes some very important discoveries by experiment 

 in the following passage, which I quote from his paper, 



'The following experiments were made wit]i a view to determine with greater 

 certainty the causes of the refrigeration in the above instances.* To discover 

 ■whether the cold produced by a living animal placed in air hotter than its body 

 be not greater than what would be produced by an equal mass of inanimate matter. 

 Dr. Crawford took a living and a dead frog, equally moist, and of nearly the same 

 bulk, the former of which was at 67°, the latter at 68°, and laid them on flannel in 

 air which had been raised to 106°. In the course of twenty-five minutes the order 

 of heating was as annexed.^ 



' The thermometer being introduced into the stomach, the internal heat of the 

 animals was found to be the same with that at the surface. Hence it appears 

 that the living frog acquired heat more slowly than the dead one. Its vital powers 

 must therefore have been active in the generation of cold. 



' To determine whether the cold produced in this instance depended solely on 

 the evaporation from the surface, increased by the energy of the vital principle, a 

 livino' and dead frog were taken at 75°, and were immersed in water at 98°, the 

 living frog being placed in such a situation as not to interrupt respiration.^ 



' These experiments prove that living frogs have the faculty of resisting heat, 

 or producing cold, when immersed in warm water ; and the experiments of Dr. 

 Fordyce prove that the human body has the same power in a moist as well as in 

 a dry air ; it is therefore highly probable that this power does not depend solely on 

 evaporation. 



' It may not be improper here to observe that healthy frogs in an atmosphere 

 above 70° keep themselves at a lower temperature than the external air, but are 

 warmer internally than at the surface of their bodies ; for when the air was 77° a 

 frog was found to be 68°, the thermometer being placed in contact with the skin ; 

 but when the thermometer was introduced into the stomach, it rose to 70^°. It may 



1 Observations by Governor Ellis in 17.58 ; teachings of Dr. Cullen prior to 1765 ; 

 very daring and important experiments by Dr. Fordyce on himself in heated rooms, 

 communicated to the Royal Society of London in 1774. 



- In the two following experiments the thermometers were placed in contact with 

 the skin of the animals under the axillee. — Okig. 



3 In the above experiment the water, by the cold frogs and by the agitation 

 which it suffered during their immersion, was reduced nearly to 911°. — Ohig. 



