Every optician now exercised his talents in improving, as he called it, the microscope; in other words, in varying its construction, and rendering it different from that sold by his neighbour. Their principal object seemed to be, only to subdivide the instrument, and make it lie in as small a compass as possible; by which means, they not only rendered it complex and troublesome in use, but lost sight also of the extensive field, great light, and other excellent properties of the more ancient instruments; and, in some measure, shut themselves out from further improvements on the microscope. Every mechanical instrument is susceptible of almost infinite combinations and changes, which are attended with their relative advantages and disadvantages: thus, what is gained in power, is lost in time; “he that loves to be confined to a small house, must lose the benefit of air and exercise.” The microscope, nearly at the same period, gave rise to M. Buffon’s famous system of organic molecules, and M. Needham’s incomprehensible ideas concerning a vegetable force and the vitality of matter. M. Buffon has dressed up his system with all the charms of eloquence, presenting it to the mind in the most agreeable and lively colours, exerting the depths of erudition in the most interesting and seducing manner to establish his hypothesis, making us almost ready to adopt it against the dictates of reason, and the evidence of facts. But whether this great man was misled by the warmth of his imagination, his attachment to a favourite system, or the use of imperfect instruments, it appears but too evident, that he was not acquainted with the objects whose nature he attempted to investigate; and it is probable, that he never saw[18] those which he supposed he was describing, continually confounding the animalculæ produced from the putrifying decomposition of animal substances, with the spermatic animalculæ, although they are two kinds of beings, differing in form and nature; so that the beautiful fabric attempted to be raised on his hypothesis, vanishes before the light of truth and well conducted experiments. [18] Porro Buffonius, ut cum illustris viri venia dicam, omnino non videtur vermiculos seminales vidisse. Diuturnitas enim vitæ quam suis corpusculis tribuit, ostendit non esse nostra animalcula (id est, spermatica) quibus brevis et paucarum horarum vita est. Haller Physiol. tom. 7.