Page:Popular Science Monthly Volume 25.djvu/828

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THE POPULAR SCIENCE MONTHLY

This inhibition may he brought about by nervous impulses coming from certain sensory nerves as those of sights touchy hearing.

It may also be brought about by impulses or changes arising in the cortex itself.

The inhibited cortex, and probably also inhibited lower centers of the brain, send out inhibitory impulses to all other parts of the central nervous system, so that the mesmerized man or animal gradually passes into a state of torpor, or even of complete anæsthesia.

The phenomena of the excitable stage of mesmerism are proximately determined by the possibility of exciting any particular center alone, without exciting at the same time other centers by which its activity is normally controlled. In lower animals this stage is less marked in consequence of a greater interdependence of the various parts of the central nervous system.

I would expressly state that I regard this theory only as provisional. Further, I am quite conscious that it is very imperfect. A complete explanation of the phenomena of mesmerism and of its allied states can only be given when we have a complete knowledge of the structure and functions of all parts of the central nervous system. But I have not much doubt that the explanation of the main features of mesmerism will be found when we are able to answer the question, What is inhibition? And it is some comfort to think that the answer awaits us in the comparatively simple nervous system of the lower animals. I would not be understood to mean that variation of blood-supply and various other events are of no influence in producing mesmeric phenomena; I think, however, that these events are of secondary importance only.

 
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PROTECTION AGAINST LIGHTNING.
II.

IN the year 1875 the Meteorological Society of London was moved to follow the lead of the French meteorologists in reference to lightning-conductors, and to appoint a Lightning-Rod Committee. From the report made to the society by the council in the following year, it appears that the objects contemplated in this action were "an investigation and record of accidents from lightning, an inquiry into the principles involved in the protection of buildings, the diffusion of exact information regarding the best form and arrangement for lightning-conductors, and the consideration of all phenomena connected with atmospheric electricity."[1] It is obvious that in its first conception this committee was intended to be essentially one of investigation and

  1. See "Quarterly Journal of the Meteorological Society," vol. iii, p. 75.