072 THEORY OF MECHANICAL AND 



is, that under such circumstances,, there is very 

 little caloric transferred to the solids in combina- 

 tion with the blood, which therefore returns to the 

 right side of the heart, of nearly the same tem- 

 perature, florid hue, and quantity of organic par- 

 ticles, as when it left the lungs. Hence it is, that 

 when the system is raised above the natural 

 standard, as during immersion in the hot bath, 

 or surrounded by an atmosphere from five to ten 

 or more degrees above the healthy temperature 

 of the body, as in the tropical portions of Africa, 

 India, New Holland, and South America, during 

 the heat of the day, all the powers of mind and 

 body are prostrated, attended with syncope, apo- 

 plexy, and frequently death, if not relieved by 

 cooling ablutions, by which the system is re- 

 duced to its natural plus and minus condition of 

 arterial blood and of the solids. For it is a certain 

 fact, that without this essential condition, none of 

 the vital functions could be carried on. 



The dynamical agency of caloric is not less 

 essential to the movements of a steam engine, 

 than to the muscular power of animals, and the 

 activity of all their functions. In both cases, it 

 is obtained by the combustion of carbon and hy- 

 drogen. In the former, it is evolved in the fur- 

 nace, communicated to the boiler, where it unites 

 with water, and converts it into an elastic gas, 

 which, by acting on the piston, sets all parts of 

 the machine in motion, whereas in the latter, it 



