"It is supposed by some physiologists that the essential cells of nerves do not actually touch, but are separated by a narrow gap which widens in sleep while it narrows almost to extinction during mental activity. THIS CONDITION IS SO SINGULARLY LIKE A BRANLY OR LODGE COHERER [a device which led to the discovery of wireless telegraphy] AS TO SUGGEST A FURTHER ANALOGY. The structure of brain and nerve being similar, it is conceivable that there may be present masses of such nerve coherers in the brain, whose special function it may be to receive impulses brought from without, through the connecting sequence of ether waves of appropriate order of magnitude. Roentgen has familiarized us with an order of vibrations of extreme minuteness as compared with the smallest waves with which we have hitherto been acquainted; and there is no reason to suppose that we have here reached the limit of frequency. It is known that the action of thought is accompanied by certain molecular movements in the brain, and here we have physical vibrations capable from their extreme minuteness of acting direct upon individual molecules, while their rapidity approaches that of internal and external movements of the atoms themselves. A formidable range of phenomena must be scientifically sifted before we effectually grasp a faculty so strange, so bewildering, and for ages so inscrutable, as the direct action of mind upon mind." Human Electro-Magnetism Professor Bain, another eminent authority, tells us: "The structure of the nervous substances, and the experiments made upon the nerves and nerve-centres, establish beyond a doubt certain peculiarities as belonging to the force that is exercised by the brain. This force is of a current nature; that is to say, a power generated at one part of the structure is conveyed along an intervening substance and discharged at some other part. The different forms of electricity and magnetism have made us familiar with this kind of action." Professor Draper, another eminent authority, says: "I find that the cerebrum is absolutely analogous to in construction to any other nervous arc. It is composed of centripetal and centrifugal fibres, having also registering ganglia. If in other nervous arcs the structure is merely automatic, and can display no phenomena of itself, but requires the influence of an external agent--the optical apparatus inert save under the influence of light, the auditory save under the impression of sound--the cerebrum, being precisely analogous in its elementary structure, presupposes the existence of some agent to act through it."