And what is that great secret? Simply that its activity is electric in its nature. So true is this that, if stimulated by a current from the outside, it will, at different points, perform its functions of moving hand, lip, eye, or other member. It is demonstrably an electrical apparatus. It is also well established that the fibres of nerve-cells connect to make thinking possible— that the electric current is turned off and on constantly within us. In short, it is known that fibre and brain are the great originals of the latest order of apparatus for communication. But those whom we may still call the tool-makers of the world do not wait for indications from the brain specialist! They are forging far ahead, making "tools" for which the brain itself is not absolutely known to offer any prototype. They were on the untrodden path already, even in the days of Dubois Raymond. For, in 1838, Steinheil was dreaming of wireless telegraphy. Even then he began to show "how an indication having no connexion with the multiplier generates currents in that multiplier through the excitation of the ground above." Yet ten years ago most people were doubtful about the success of telegraphy without wires. They were doubtful; but very quickly, at last, the success of wireless telegraphy was assured, and already it is a thing grown
