sertations in defence of the circulation, we perceive the apostles of all new truths, namely, the youthful, at work. Were there not successive generations of men, the world would stand still; the death of the individual was not merely a necessary condition to the enjoyment of life by successive generations, but essential also to the onward progress of mankind. No man who had attained to the age of 40 years, it is said, was found to adopt the doctrine of the circulation; it had to win its way under the safeguard of the Drakes and Leroys especially, that is to say, of the youthful and unprejudiced spirits of the age.
Twenty years after the publication of the 'Exercitatio de Motu Cordis et Sanguinis,' Joannes Riolanus, the younger, was delivered of his 'Encheiridium Anatomicum' (8vo. Lugd. Batav. 1648), in which he makes a vain attempt to supplant the Harveian doctrine by a new and most extraordinary one of his own, so incongruous and unlikely, that in these days we are irresistibly led to form no very high estimate of the intellect that could have engendered it. It looks to us, indeed, at this time, like condescension on the part of the great English anatomist, that he noticed the abortion of such a tyro in animal physics as the French professor here approves himself. Harvey's genius could surely have felt no real respect for the illogical intellect of Riolan. But Harvey, when he noticed Riolan's publication, was in want of a good occasion for a farther development of his own views; and so he seized on the Parisian professor, respectable from his position in the university, and as physician to the queen mother of France, and made him his vehicle—his placard bearer. Harvey, besides, was personally acquainted with Riolan, who had accompanied Mary de Medicis to England on a visit to her daughter the Queen of Charles the First; on which occasion Harvey and Riolan had even held conversations on
