II. The Croonian Lecture. On the existence of nerves in the placenta

In the Lecture which I gave last year, I attempted to trace the structure of the human brain to as great a degree of minuteness as is consistent with accuracy, by observing its appearance in the field of the microscope. This I should not have ventured to do under any other circumstances, than being assisted by the eye of Mr. Bauer in examining the appearances, and in having correct representations of them under his hand, to lay before the Society. Without these peculiar advantages, I should have been afraid of being led into error, either by the fallacies to which microscopical observations are liable in themselves, or those which so frequently occur when the same eye is not employed both in ascertaining the appearances, and in directing the pencil by which they are delineated.