CHARLES, an eminent naturalist and philosophical writer, born at Geneva on the 13th March 1720, of a French family whose religious principles had obliged them to leave their native country. At the early age of sixteen his attention was so deeply engaged by the study of Pluche's Spectacle de la Nature, that it seems to have given a bias to his future studies. The history and habits of the antlion, formica leo, particularly attracted his attention. He discovered the haunts of this curious insect, studied its habits, and added many observations to those of Pluche and Reaumur. Reaumur's memoir on Insects he also perused with great avidity; and to the observations and experiments of that naturalist Bonnet added many new facts, the detail of which he communicated to Reaumur; who was not less surprised than pleased to find so much sagacity and acuteness of research exhibited by a youth of eighteen.

Bonnet had been destined by his father for the profession of the law; but the bias of his mind leaned too strongly to natural history to permit him to occupy his attention with other pursuits, and the study of law was submitted to merely as a task. In 1738 and 1739 he sent to Reaumur many interesting observations on different species of caterpillars; and in 1740 he communicated a paper to the Academy of Sciences respecting the propagation or multiplication of aphides, or tree-lice, without actual conjunction. This question, which had been left unsettled by Reaumur, was now determined by decisive experiments; and his paper on the subject obtained for Bonnet the honour of being admitted a corresponding member of the Academy. His experiments on the generation of these insects were conducted with such close attention and minuteness of research as permanently to affect his eyesight. In the year 1741 he instituted a set of experiments on the division of worms; and he found that many species possessed in some degree the same reproductive power as the polypus. In the following year his investigations and experiments were directed to the respiration of caterpillars and butterflies; and he proved that this function was performed by means of pores to which the name of stigmata has been given. It was about the same time that he made some curious discoveries respecting the tanita, Bonnet, or tape-worm. In 1743, when he became a doctor of laws, he procured a ready dispensation from the further prosecution of his legal studies, which he now relinquished forever. A memoir on insects which he communicated to the Royal Society of London in the same year procured his admission into that body. Next year he published his *Insectology*, and prefixed to it a preface, in which he exhibits a philosophical sketch of his ideas concerning the system of the development of germs, and the scale of organized beings. This work was in general well received, though by some of the journals it was taxed with a want of delicacy in the descriptions of the mode of propagation of tree-lice.

Bonnet's health now began visibly to decline. His eyes particularly were affected with severe pains, which obliged him to lay aside the use of the microscope, and to forego for a time all reading and writing. Like a true philosopher, he bore his afflictions with patience; yet, although he was interdicted from all observation, his mind was fully occupied in reflection. He was at last restored to tolerable health; but he never could employ his eyes with the same freedom as formerly. About the year 1746 he undertook a course of experiments on the vegetation of plants in moss and other substances; and in the following year his researches were directed to the functions of the leaves of plants, with the view of ascertaining the different action of the two sides of the leaf. He also made experiments on the ascent of the sap; and to determine whether it rose by the bark or wood, he employed coloured injections. This investigation, with some observations which he made on vegetable monsters, was the foundation of one of his most interesting and original works, entitled *Inquiries into the Use of the Leaves of Plants*, Leyden, 1754, 4to. A supplement was added to it in 1779.

Bonnet's inquiries in natural history now led him on to physiology and metaphysics, where he followed in the footsteps of Malebranche and Leibnitz. The first fruit of his meditations was a kind of abridgment of the materials he had collected, under the title of an *Essay on Psychology*, published in London in 1754, but without his name, nor did he acknowledge it till nearly thirty years afterwards. This work contains, in a concise form, the fundamental principles of his philosophy; some account of which will be found in Mr Stewart's *Dissertation*, §§ 3, 4, and 5. It met with some censure, yet its success was brilliant. His next work was a development of the same subject. In 1760 he published, at Copenhagen, in 4to, his *Analytical Essay on the Faculties of the Soul*, in which, like Condillac, he supposes a statue organized like the human body, which by degrees he animates, and shows how its ideas would arise from impressions on the organs of sense. This essay was well received, though it subjected the author to a charge of materialism, which it cannot be denied was the logical result of its principles. In the case of Bonnet, however, the charge was of easy refutation. His retired and studious habits, together with his deafness and other bodily infirmities, rendering domestic comforts more essential to him, he married, in 1756, a lady of the family of De la Rive, and with her he passed thirty-seven years of domestic happiness. The celebrated Saussure was nephew to his wife, and was brought up as a son by Bonnet, who had no children of his own.

His next work, *Considerations on Organized Bodies*, 2 vols. 8vo, Amst. 1762, was properly the physical part of his great system. Its principal objects were, to give in an abridged form all the most interesting and well-ascertained facts respecting the origin, development, and reproduction of organized bodies; to refute the different systems founded upon epigenesis; and to explain and defend the system of germs. His *Contemplation of Nature*, Amst. 1764–65, 2 vols. 8vo, was a popular work, in which the principal facts relative to the different orders of created beings are displayed in a manner both instructive and entertaining, and set off by the charms of an eloquent style; with a continual reference to final causes, and proofs of creative wisdom and benevolence. It has been translated into most of the European languages. The concluding work of Bonnet was his *Paléontologie Philosophique*, Geneva, 1769, 2 vols. 8vo. In this he treats of the past and future state of living beings, and supports the idea of the survival of all animals, and the perfecting of their faculties in a future state. Attached to this work is *An Inquiry into the Evidences of the Christian Revelation, and the Doctrines of Christianity*, which, with a treatise *On the Existence of God*, was published separately at Geneva in 1770 and 1771.

Again directing his attention to natural history, he published in 1773, in *Rozier's Journal*, a memoir on the method of preserving insects and fishes in cabinets; and, in the following year, another on the loves of plants, originating in the discovery of a kind of cleft or mouth in the pistil of a lily. This was followed by various memoirs and observations on subjects in natural history. His reputation was now fully established. Most of the learned societies of Europe enrolled him among their members; and in 1783 he was elected into the small and very select number of foreign associates of the Academy of Sciences at Paris. Although attached by inclination to scientific pursuits, he did not entirely withdraw from public duties. He entered into the great council of the republic in 1752, and kept his seat in it till 1768; having frequently distinguished himself by his manly eloquence in support of moderate measures, and his zeal in the cause of morals and religion. The last twenty-five years of his life he passed entirely in the country, in a simple and uniform mode of life, happy in an easy competence, and in a small circle of friends. It appears that he was for some time engaged in the education of youth, in which employment he secured the warmest attachment of his pupils. His health was greatly impaired by the excessive labour he bestowed for nearly eight years on a collective edition of his works. This appeared at Neuchâtel in 1797, in 8 vols. 4to, and 18 vols. 8vo. Besides the works already mentioned, it contains a number of smaller pieces, both in natural history and metaphysics. They are all written in French. After a long and painful illness, which he bore with exemplary patience and serenity, this excellent man died on the 20th May 1793, at the age of seventy-three. Public honours were rendered to his remains by his fellow-citizens, and his funeral oration was pronounced by his illustrious friend and kinsman M. de Saussure.