After considering all these circumstances Mr. Needham conjectures, that the supposed spermatic animals might possibly be only natural machines, substances much more simply organized than the bodies of animals. I have seen with the microscope, these machines in the calmar, and the description he gives of them, is very faithful and exact. His observations then shew us, that the seminal liquor is composed of parts which seek to be organized; that it, in fact, produces organized substances, but that they are not as yet, either animals or organized substances, like the individual which produced them. We might suppose, that these substances are only instruments which serve to perfect the seminal liquor, and strongly impel it; and that it is by their brisk and internal action, that it most intimately penetrates the seminal liquor of the female. CHAPTER VII. COMPARISON OF MY OBSERVATIONS WITH THOSE OF LEEUWENHOEK. Although I made the preceding experiments with all the circumspection possible; and although I repeated them a number of times, I am persuaded that many things escaped my notice; I have only related what I saw, and what all the world may see, with a little art and much practice. In order to be free from prejudices, I endeavoured to forget what other naturalists asserted to have seen, conceiving that by so doing, I should be more certain of only seeing in fact what really appeared; and it was not till after I had digested my observations, that I compared them with those of Leeuwenhoek, &c. I by no means pretend to have greater abilities in microscopical observations than that great naturalist, who passed more than sixty years in making various experiments. Notwithstanding the authority his observations may justly claim, it is surely permitted to examine and compare others with them. Truth can only be gained by such examinations, and errors discovered, particularly as we do it without any partiality, and in the sole view of establishing something fixed and certain on the nature of those moving bodies seen in the seminal liquors.