3fiS - COOLING OF ANIMALS EXPOSED TO GREAT HEAT. ^ 



ture of water ifiperiments, made with care, have convinced me, that frogs 



which they are. constantly acquire the temperature of the water in which 



they are immersed, let its heat be what it may, and that ia 



this respect there is no difference between dead and living 



frogs *. 



These are all the experiments, as far as I know, that 

 have been tried to ascertain what would happen, when men 

 or animals are exposed to a high degree of heat, without 

 any evaporation being able to take place from the surface 

 New expert- of thcir bodies. Their insufficiency is evident. New ones 

 meiitsmade therefore cannot be uninteresting, and these I have at- 

 tempted. 

 on the plan of With this view I had recourse to the means employed by 

 or yce. -p^^ Fordyce, but with this diffierencej instead of trying 

 the experiments with man, I employed animals of small 

 size, that their mass might be more quickly heated. In 

 fact it is well adapted to the end proposed ; for it is ob- 

 vious, that if an animal be placed in air loaded with 

 vapour, there can be no evaporation of the fluid exhaled 

 either on the surface of its body, or from its lungs ; and 

 yet it may continue the exercise of its functions as freely as 

 in dry air. The apparatus I employed allowed me to dis- 

 tribute the vapour pretty uniformly throughout the space 

 occupied by the animals, and to regulate the quantity at 

 pleasure. The following is a description of it. 

 The apparatus AA, PI. X, fig. 1, is a box, about forty inches high, 

 described. twenty broad, and sixteen deep : divided into two com- 



partments by an open partition, shown at n n in the section, 

 fig. 2. At act is a door, sliding in a groove, and opening 

 into the upper chamber; in which is a circular wicker cage, 

 2 2 fig 2, with a door opening opposite that of the outer 

 box. In this cage the animals were placed. A thermometer, 

 with a very long stem and small bulb, is fixed in the centre 

 of this cage. It is protected from injury by an open 

 wicker case, »im fig. 2; and reaches above the top of the 

 box, fig. 1, at 6, where it is graduated. The vapour is 

 generated in a small tin boiler C C, heated by means of the 



* See my Essay on the Effects produced in the Animal Eco- 

 nomy by a high Degree of Heat, p. 51 and foil. 



furnace 



