ANIMALCULA OF INFUSION'S. 41' 



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tions. But, if the life of animals in exiilence is 

 fo little known, notwithftanding all the efforts of 

 modern phyfiology, much more obfcure mufl be 

 the life of an animal concealed or concentrated 

 in an e^g. Certainly we may conclude, that the 

 life of an animal in the egg is moft feeble com- 

 pared with that of the animal produced. Dur- 

 ing the firft hours of incubation, the animation 

 of the chicken is indicated only by the beating 

 of the heart. Life before this is^ flill more feeble: 

 it is a leffer life, doubtlefs fuch as that in the 

 germs of infe£ls eggs previous to their having 

 experienced the degree of heat neceflary for ex- 

 elufion. Can this moft faint and feeble anima- 

 tion be any reafon why it may endure more heat 

 than after it is developed ? Certain it is, that 

 animals, when in a flate of very feeble life, which 

 hardly merits the name of animation, do refifl 

 external injuries with much greater impunity than 

 wheri moft vivacious ( i ). Thus-, if we cut off 

 ^ - the 



(i) This certainly depends very muck on the nature 

 of the hijury to which the germ or animal is expofed, for 

 the imperceptible agency of particular fubftances, whofe 

 nature we are little acquainted with, are noxious. Thus 

 MichelottL incloled a number of eggs in glafs veffels, fome 

 of which admitted the rays of light, and others excluded 

 them. Few or none in the former were hatched; whence, 

 from a feries of experim.ents, he concludes that light is 

 prejudicial to the developement of all the germs' of ant^ 

 jnals,- and the fame with refpeft to vegetable germs,— T., 



