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ADDITIONAL NOTES. VIII. 

 REPRODUCTION. 



But Reproduction with ethereal fires 



New life rekindles, ere the first expires. CANTO II. 1. 13. 



I. THE reproduction or generation of living organized bodies, is 

 the great criterion or characteristic which distinguishes animation 

 from mechanism. Fluids may circulate in hydraulic machines, or 

 simply move in them, as mercury in the barometer or thermometer, 

 but the power of producing an embryon which shall gradually acquire 

 similitude to its parent, distinguishes artificial from natural organiza- 

 tion. 



The reproduction of plants and animals appears to be of two kinds, 

 solitary and sexual; the former occurs in the formation of the buds 

 of trees, and the bulbs of tulips; which for several successions gene- 

 rate other buds, and other bulbs, nearly similar to the parent, but 

 constantly approaching to greater perfection, so as finally to produce 

 sexual organs, or flowers, and consequent seeds. 



The same occurs in some inferior kinds of animals; as the aphises 

 in the spring and summer are viviparous for eight or nine generations, 

 which successively produce living descendants without sexual inter- 

 course, and are themselves, I suppose, without sex; at length in the 

 autumn they propagate males and females, which copulate and lay 

 eggs, which lie dormant during the winter, and are hatched by the 

 vernal sun; while the truffle, and perhaps mushrooms amongst vege- 

 tables, and the polypus and tjenia amongst insects, perpetually propa- 

 gate themselves by solitary reproduction, and have not yet acquired 

 male and female organs. 



Philosophers have thought these viviparous aphides, and the tsenia, 

 and volvox, to be females ; and have supposed them to have been im- 

 pregnated long before their nativity within each other; so the tsenia 

 and volvox still continue to produce their offspring without sexual 



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