Charles Bonnet, a Swiss naturalist and philosopher, born in Geneva, March 13,1720, died there, May 20, 1793. He was educated for the law, but reading Pluche's account of the formica leo, he undertook to find this insect for himself. This search interested him in many other insects. He read other works, and made further observations, discovering several unde-scribed species, and becoming a naturalist of rare attainments at the age of 1G. At 18 he communicated to Reaumur several interesting facts, and at 20 his discovery that several generations of aphides are produced by a viviparous succession of females without the males, for which he was elected a corresponding member of the French academy of sciences. Learning of Trembley's experiments on the reproduction of certain polyps by bisection, Bonnet experimented, and discovered that certain so-called worms could be multiplied by the same process. He published these discoveries in his Traite d'insectologie (1745). In 1754 he published De l'usage desfeuilles, treating upon vege table physiology, and in 1762-'8 Considerations sur les corps organises, embodying his views on the origin and reproduction of organic forms of life. The failure of his sight drove him from the field of actual observation to that of speculative philosophy.
His Essai de psychologic appeared in 1754, and his Essai analytique dis facultes de l'ame in 1760. In his Contemplation de la nature (1764-'5) he tried to construct a chain of nature from the lowest organism up to the Deity. His Palingenesie philo-sophique (.1770) puts forth the idea that the souls of animals are immortal and rise progressively in the scale of being. He published in 1771 Recherches philosophiques sur les preuxes da Christianisme, a defence of revelation. His complete works were published at Neufchatel, before his death, in 8 vols. 4to, and with illustrations, in 18 vols. 12mo.