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present day had existed in the time of Harvey, we might have remained for long years ignorant of the action of the heart and of the circulation; and the knowledge of disease and the best curative measures would have remained unknown; or Harvey might have returned to Padua to make his experiments. If it were possible, it might be well for those who raise such a vehe- ment outcry against the means often best fitted for physiological research, namely, experiment on living animals, if they ceased to partake of the advantages which humanity has received from these re- searches.
Time would fail me to describe the ad- vances made in physiological science since the time of Harvey. The lacteal vessels were discovered by Aselli, and more fully by Pecquet of Dieppe, who described the mesenteric vessels, traced them to the receptaculum chili and onward to the thor- acic duct. It was a hundred years after Harvey's work that Stephen Hales used a manometer to estimate the pressure of the blood, and afterwards Poiseuille introduced
