OF NATURAL HISTORY. 33 



The beauties of Nature have been juftly celebrated in the unifor- 

 mity of her produdtions. This uniformity was early remarked, and 

 gave rife to the ancient divifion of animals into viviparous and ovi- 

 parous, which continued to be adopted as an univerfal maxim till 

 within thefe hundred years. Before this period, it was believed by 

 philofophers, that all animals were either brought forth alive, or 

 hatched from eggs. Among the ancients, indeed, and even down 

 to the time of the celebrated Redi, this maxim included chiefly the 

 more perfeft animals ; for, with regard to moft of the infedt tribes, 

 they imagined that thefe were produced by putrefadion, and the 

 admixture of particular kinds of matter. But Redi, by a feries of 

 unqueftionable experiments, exploded the dodlrine of the equivocal 

 generation of infeds ; and then the maxim, without farther invefti- 

 gation, was extended to the whole animal kingdom. Redi's experi- 

 ments and remarks turned the attention of philofophers to the mi- 

 nuter tribes of animals. In the courfe of a few years, accordingly, 

 feveral eminent men arofe. Reaumur, Bonnet, Trembley, Ellis 

 Spalanzani, and a multitude of other writers, opened new views- 

 with regard to the manners and oeconomy of animated beings. M. 

 Bonnet has furnllhed inconteftible evidence, that feveral fpecies of 

 the puceron, or vine-fretter, are both oviparous and viviparous. In 

 fummer, thefe infedls bring forth their young alive; but, in autumn 

 they depofit eggs upon the bark and branches of trees. Here the 

 intention of Nature is apparent. The puceron is unable to furvive 

 the winter colds ; and, therefore, though viviparous during the 

 warm months, the fpecies could not be continued without this wife 

 provifion. The puceron, it fhould appear, is naturally difpofed to 

 produce live young. The foetus is inclofed in a membrane, which, 

 like that of the larger animals, burfts before exclufion. But, when 

 the cold feafon commences, the general texture of the animals, as 

 t E well 



* Traite d'lnfeftologie, par C. Bonnet, torn. i. p. 194. — 202. 



