Page:Popular Science Monthly Volume 14.djvu/317

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303
BEGINNING OF NERVES.

me, and again I shall lose what I give you for copyright. I must, therefore, reduce the amount which I give for the copyright." Moreover, I believe that the reduction in the value of copyrights would be much greater than the facts justified. In the first place, the publisher himself would look to the possibility of reprinting with a fear beyond that which actual experience warranted. Frequently a suggested small danger acts upon the mind in a degree out of all proportion to its amount. Take such a case as the present smallpox epidemic, in which you find one person in 30,000 dies in a week; in which, therefore, the risk of death is extremely small. Look at this actual risk of death and compare it with the alarms that you find prevailing among people. It is clear that the fear of an imagined consequence of that kind is often much in excess of the actual danger. Similarly, I conceive that the publisher himself would unconsciously over-estimate the danger of reprints. But beyond that he would exaggerate his over-estimate as an excuse for beating down copyright. He would say to the author: "You see this danger; I cannot face so great a risk without guarding myself; and you must submit to a large reduction."

(Mr. Spencer was subsequently called before the committee again, and we shall give his interesting evidence next month.)

 

THE BEGINNING OF NERVES IN THE ANIMAL KINGDOM.
By GEORGE J. ROMANES.

NERVE-TISSUE universally consists of two elementary structures, viz., very minute nerve-cells and very minute nerve-fibres. The fibres proceed to and from the cells, so in some cases serving to unite the cells with one another, and in other cases with distant parts of the animal body. Nerve-cells are usually found collected together in aggregates, which are called nerve-centres or ganglia, to and from which large bundles of nerve-fibres come and go.

To explain the function of nerve-tissue, it is necessary to begin by explaining what physiologists mean by the term "excitability." Suppose that a muscle has been cut from the body of a freshly-killed animal; so long as it is not interfered with in any way, so long will it remain quite passive. But every time a stimulus is supplied to it, either by means of a pinch, a burn, an electrical shock, or a chemical irritant, the muscle will give a single contraction in response to every stimulation. And it is this readiness of organic tissues to respond to a suitable stimulus that physiologists designate by the term "excitability."