This page has been proofread, but needs to be validated.

20

made no use of, had faith in the fact which has given to mankind the power of controlling small-pox.

In consequence of this faith in facts he overlooks none; he passes by none. Now a common error is to think some facts more important than others; but all are important, and if one is left out, a whole heap may fall asunder. Now Harvey omits nothing; he commences with the most obvious, and proceeds step by step; nothing is blurred; nothing is left ill-defined. His work was composed before the Novum Organon was published, but it has been well said by Willis that it might have been planned on the model of that system.

The marvellous clearness of Harvey’s treatise on the Action of the Heart and Circulation is quite unsurpassed. It is said that not one of his hearers at this College ever doubted his doctrine, and we can well imagine this when we see the way in which the facts are laid in order; first this, then that, then a third, and so the mind is led from step to step until the