206 



CLASS AVES. 



hen could communicate to them, became hatched of them- 

 selves. The natural conclusion from this was, that the only 

 office of the hen in incubation was that of an agent to trans- 

 mit the quantity of caloric necessary for the development of 

 the embryo, and that any other heat, providing that it was 

 absolutely similar in energy and duration, would produce the 

 same effect. 



It was only necessary then to imitate the process which 

 chance had pointed out, and to choose a situation where the 

 eggs would be subjected to the same temperature as under 

 the female which had laid them. Nothing seemed more easy 

 of discovery than this ; all nations were interested in finding 

 it out, and yet it was only in Egypt that modes sufficiently 

 perfect for this purpose were invented, and from which any 

 considerable advantages were derived. 



The ovens, or hatching-places, invented by the priests of 

 that country, furnished, in ancient times, one hundred mil- 

 lions of chickens in the year ; and at present, when the popu- 

 lation of that country is less, and the ovens are managed by 

 simple peasants, who inherit the secret of those ancient priests, 

 they still produce thirty millions in the same space of time. 

 In the records of other nations, from the highest antiquity to 

 our own days, we find no accounts of eggs artificially hatched, 

 a few excepted, which were brought to perfection by methods 

 very different from those of the Egyptians. 



It is not, however, to be doubted, but that the success 

 obtained by the Egyptian mode, must have excited the emu- 

 lation of the Greeks and Romans. But as they could not 

 prevail on the Egyptian priests to reveal their secret, and 

 as they were misled by the opinion of Aristotle that those 

 priests employed the heat of dung for this purpose, their 

 attempts in this way were too unproductive to induce them 

 to form establishments worthy of the notice of history. They 



