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Rh apart, in their own way, and with all attainable precision. The inductions are the maxims of practice, purified, in the first instance, by wide comparison and by the requisite precautions.

I thus propose to remove from the science of education matters belonging to much wider departments of human conduct, and to concentrate the view upon what exclusively pertains to education—the means of building up the acquired powers of human beings. The communication of knowledge is the ready type of the process, but the training operation enters into parts of the mind not intellectual—the activities, and the emotions; the same forces, however, being at work.

Education does not embrace the employment of all our intellectual functions. There is a different art for directing the faculties in productive labor, as in the professions, in the original investigations of the man of science, or the creations of the artist. The principles of the human mind are applicable to both departments, but, although the two come into occasional contact, they are so far distinct that there is an advantage in viewing them separately. In the practical treatise of Locke, entitled "The Conduct of the Understanding," acquisition, production, and invention, are handled promiscuously.

—The science of physiology, coupled with the accumulated empirical observations of past ages, is the reference in finding out how to rear living beings to the full maturity of their physical powers. This, as we have said, is quite distinct from the process of education.

The art of education assumes a certain average physical health, and does not inquire into the means of keeping up or increasing that average. Its point of contact with physiology and hygiene is narrowed to the plastic or acquisitive function of the brain—the property of fixing or connecting the nervous connections that underlie memory, habit and acquired power.

But as physiology now stands, we soon come to the end of its applications to the husbanding of the plastic faculty. The inquiry must proceed upon our direct experience in the work of education, with an occasional check or caution from the established physiological laws. Still, it would be a forgetting of mercies to undervalue the results accruing to education from the physiological doctrine of the physical basis of memory.

On this subject, physiology teaches the general fact that memory reposes upon a nervous property or power, sustained, like every other physical power, by nutrition, and having its alternations of exercise and rest. It also informs us that, like every other function, the plasticity may be stunted by inaction, and impaired by over-exertion.

As far as pure physiology is concerned, I invite everybody to reflect on one circumstance in particular. The human body is a great aggregate of organs or interests—muscles, digestion, respiration, senses, brain. When fatigue overtakes it the organs generally suffer;