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apprehension of the will. At this point, physical inquiry has been very fruitful in its influence on philosophy.

Says Bain, page, 63: "The conducting power of nerve fibre is attended with nervous waste, and the substance has to be constantly renewed from the blood, which is largely supplied to the nerves, although not so largely as to the vesicles. If now we compare this liability to waste and exhaustion, with the undying endurance of an electric wire, we shall be struck with a very great contrast. The wire is doubtless a more compact, resisting and sluggish mass; the conduction requires a certain energy of electric action to set it agoing, and in the course of a great distance becomes faint and dies away. The nerve, on the other hand, is stimulated by a slighter influence, and propagates that influence with increase, by the consumption of its own material. The wire must be acted on at both ends, by the closure of the circuit, before acting as a conductor in any degree; the nerve takes fire from a slight stimulus, like a train of gunpowder, and is wasted by the current that it propagates. If this view be correct, the influence conveyed is much more beholden to the conducting fibres, than electricity is to the copper wire. The fibres are made to sustain or increase the force at the cost of their own substance.

"The nerve force is propagated more slowly than an electric current through a wire. The rate has been estimated at about two hundred feet a second as an average. It is to be remarked, that a nerve is not a simple conductor, but is supposed to consist of a countless number of molecules, each of which has playing round it an electrical current, or currents, which are an obstacle to the simple or direct propagation. There is always a certain delay in passing through the nerve centres; a reflex movement occupies from one-thirtieth to one-tenth of a second under favorable circumstances, which is more time than would be required