148 GROWTH AND FOOD OF ANIMALS. 



ation was disagreeable to them. Most of them retired from 

 under the slice of beef; and the few that remained perished 

 in a short time. Their death was probably occasioned by the 

 degree of heat in the pigeon's body being greater than their 

 constitution could bear. Upon the same pigeon M. de Reau- 

 mur performed another experiment. He took off the skin 

 from its thigh, laid bare the flesh, and applied immediately 

 another slice of beef full of maggots. The animals discovered 

 evident marks of uneasiness; and all of them that remained 

 on the flesh of the pigeon were deprived of life, as in the 

 former experiment, in less than an hour. Thus the degree of 

 heat that is necessary to such worms as inhabit the interior 

 parts of animals, is destructive to those species which nature 

 has destined to feed upon the flesh of dead animals. Hence 

 the worms sometimes found in ulcerous sores must belong to 

 a different species from those upon which the above experi- 

 ments were made. 



The growth of some worms, which feed upon animal or 

 vegetable substances, is extremely rapid. Redi remarked, that 

 these creatures, the day after they escaped from the egg, had 

 acquired at least double their former size. At this period he 

 weighed them, and found that each worm weighed seven 

 grains; but that, on the day preceding, it required from 

 twenty-five to thirty of them to weigh a single grain. Hence, 

 in about the space of twenty-four hours, each of these worms 

 had become from one hundred and fifty-five to two hundred 

 and ten times heavier than formerly. This rapidity of growth 

 is remarkable in those maggots which are produced from the 

 eggs of the common flesh-fly. 



Before we dismiss this subject, a few observations on that 

 power inherent in all animal bodies, of dissolving and con- 

 verting into chyle the nutritive substances thrown into the 

 stomach, merit attention. 



In order to explain the process of digestion, some physi- 

 cians and philosophers have had recourse to mechanical force, 

 and others to chemical action. The supporters of mechani- 

 cal force maintained, that the stomachs of all animals com- 

 minuted, or broke down into small portions, every species of 

 food, and prepared it for being converted into chyle. The 

 chemical philosophers, on the contrary, supported the opinion, 

 that the food was dissolved by a fermentation induced by the 

 saliva and gastric juices. The disputes which naturally arose 

 from these seemingly opposite theories, stimulated the inquiries 

 of the ingenious, and produced several curious and important 

 discoveries. 



