left it off; whereas the poet, strictly speaking, has no continuators. The Homeridæ do not represent Homer, nor do Dryden and Congreve take the place of Shakespeare. The story of natural knowledge or science, we are reminded, is a story of continued progress. "There is in it not so much as a hint of falling back--not even of standing still." The enemies of science sometimes seek to turn against it the fact that each age revises the conclusions of the preceding one. They ask, What dependence can be placed upon opinions or theories that are thus subject to change? The answer is that the science of each age is the nearest approximation which that age can make to the truth, and upon some points represents the truth with a great approach to finality of interpretation. The law of gravitation, for example, as formulated by Newton, lies at the foundation of the physics of to-day. The circulation of the blood was discovered once for all by Harvey. The true theory of the solar system was given once for all by Kepler. It is the glory of science that whatever of imperfection may lurk in a scientific theory is sure to be brought to light and corrected by subsequent observation and analysis. The learned professor dwelt briefly but forcibly upon the qualities of the scientific mind. In the first place, the scientific mind must "vibrate in unison with that of which it is in search." It is in search of truth, and it must therefore vibrate in unison with truth. The follower of science must have a truthfulness beyond that of the ordinary man, who does not set a great price upon exactness in his observations or conclusions, and readily confounds things which, superficially similar, are fundamentally different. Nature resents even the most trifling inexactness, and the careless student will find that the further he carries his inquiries the further he goes astray. The scientific mind must also be alert. The indications and hints which Nature gives are sometimes very slight, and only one who is watchful in the extreme and attentive to the smallest things will catch them. Then the problems which Nature sets are often complicated, and call for a high degree of courage and perseverance. An inquiry which seemed easy at first will suddenly become overcast by what seems the most hopeless obscurity, and the scientific worker, unless he possesses the necessary moral as well as intellectual qualities, will fail in his quest. Considering the characteristics which the pursuit of science tends to develop in its votaries, and considering that scientific method is now and has been for many years past a wonderfully devised system for carrying on research, Professor Foster is surprised that the progress of science is not even more rapid than it is. He fears that perhaps Science does not get the best minds enrolled in her service, and rather hints that our institutions of education are responsible for turning aside many who might lend great