In the marsupials it is more evident, and its excitation by electric currents evokes movements in the musculature of the crossed side of the body.
If these spark balls are set at the right distance, then when the potential difference accumulates the antenna will be charged and at some stage suddenly discharged by the discharge leaping across the spark gap. This was Marconi's original method, and the plan is still used under the name of the direct method of excitation or the plain antenna.
It is reasonable, therefore, to conclude that ornament is a stimulus to sexual selection, and this conclusion is enforced by the fact that among many comparatively nude peoples clothing is assumed at certain dances which have as their confessed object the excitation of the passions of the opposite sex.
The striking discovery was, in 1903, made by the same investigators that the spontaneous luminosity of radium gives a spectrum of a kind never before obtained without the aid of powerful excitation, electrical or thermal.
Hitherto we were entirely and still are generally confined to electrical excitation or to chemical action as in the case of flames.
Besides investigating other phenomena connected with a vacuum, he constructed an electrical machine which depended on the excitation of a rotating ball of sulphur; and he made successful researches in astronomy, predicting the periodicity of the return of comets.
The muscular wall of the blood-vessels also exhibits tonic contraction, which, however, seems to be mainly traceable to a continual excitation of the muscle cells by nervous influence conveyed to them along their nerves, and originating in the great vaso motor centre in the bulb.
Of the response of the nerve, it is found that unmistakable signs of fatigue appear even very soon after commencement of the excitation of the nerve, and the muscle ceases to give any contraction in response to stimuli applied indirectly to it through its nerve.
Larger and thicker in the rabbit, when excited it gives rise in that animal to movements of the eyes and of the fore-limbs and neck; but it is only in much higher types, such as the dog, that the cortex yields, under experimental excitation, definitely localized foci, whence can be evoked movements of the fore-limb, hind-limb, neck, eyes, ears and face.
The movements obtained by point-to-point excitation of the cortex are often evidently imperfect as compared with natural movements - that is, are only portions of complete normal movements.
Rarely can the whole action be provoked, and then only gradually, by prolonged and strong excitation of one of the requisite points, e.g.
Brain still more increased even than the motor field are:the great regions of the cortex outside that field, which yield no definite movements under electric excitation, and are for that reason known as "silent."
Theoretically the first depends on the second, for its purpose is twofold: the excitation of worthy religious emotions and the attaining of our desires; and how shall these objects be attained unless we know him whom we worship and to whom we pray?
In all but a few of the minor groups religious fervour is only too apt to degenerate into that very state of sexual excitation which devotional exercises should surely tend to repress.
Both would be seen to have a common startingpoint in the reaction against long dominant ideas which were becoming obsolete, and also in the excitation of faculties which had during the same period been accumulating energy.
Ladd and others, and the principle of self-excitation was suggested by Wilde, C. F.
Stimulants are those which lead to excitation of the mental faculties and in quantity may lead to delirium and incoherence.
To what peculiar excitation of our bodily or mental organism, it is asked, are the emotions due which make us declare an object beautiful or sublime?
In this adjustment the lowest stage is taken by 'reflex action and instinct, where Spencer the change of the organs is purely automatic. As the external complexity increases, this automatic regularity fails; there is only an incipient excitation of the nerves.
It is when the excitation is partial only, when it does not inevitably and immediately appear as action, that we have the appearance of intellect in the gap. The chief and fundamental difference between Schopenhauer and Spencer lies in the refusal of the latter to give this "adjustment" or "automatic action" the name of will.
Will, according to Mr Spencer, is only another aspect of what is reason, memory or feeling - the difference lying in the fact that as will the nascent excitation (ideal motion) is conceived as passing into complete or full motion.