2298. Afterwards it was said by those then with me that if it had not been for the microscope, by which things could be viewed that were too minute for the eye to see, that they would have supposed, for instance, the greater parts of the body, because they could not see their interiors to be a one; still less [would have supposed] it to consist of indefinites. The microscope revealed that those things they previously supposed to have been a unit contain innumerable things; for instance, that a little worm, scarce visible to the minutest ray of sight, possessed organs of sense, viscera, as many as a large animal, cerebrum, spinal marrows, pulmonary pipes, organs of generation; so that there is not a single thing, not any member whatever, but could yet be detected by the microscope as to whether or no it consisted of follicles, pipes, vessels, fibers, and whether or no a vital fluid was therein, and so forth. Thus it must be evident how much is latent only in those things that are merely corporeal and natural. What therefore may not be latent in fewer things; for whatever vital principle arises hence happens by mediate organic substances. - 1748, June 11.