Principles of human physiology / by William B. Carpenter ; edited by Henry Power.

Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: Principles of human physiology / by William B. Carpenter ; edited by Henry Power. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    Thermal; and then, prosecuting his analysis under the guidance of that idea of Power which he finds in his own sense of effort, has been brought to refer every effect to a causative Force of some kind, acting through a certain Material instrumentality:—so the Physiologist who makes the living Organism, his study, is led in the first place to refer its peculiar phenomena to a set of categories as distinct from the preceding as they are from each other ; and thence to distinguish be- tween their instrumental and their dynamical conditions, the Organic Structure and the Vital Forces which animate it. But further, as the Physicist, in proportion to the elevation of his stand-point and the com- prehensiveness of the survey he can thence take of the phenomena of the Inorganic Universe, is enabled to discern, first the mutual relation, and at last the essential unity, of all those Forces whose manifestations ap- peared so diverse when separately contrasted: so may the Physiologist, in proportion to the insight he gains into the peculiar characteristics of Vital Activity, come in the first instance to recognise the mutual relation _ of the agencies which underlie its diversified phenomena, next to perceive their fundamental unity as so many expressions of one and the same Vital Force acting through different material instrumentalities, and finally to discern the essential identity of this Force with that which maintains the ceaseless cycle of activity in the Universe at large.* 3. If, now, we inquire what it is that essentially distinguishes Vital from every kind of Physical activity, we find this distinction most characteristically expressed in the fact that a germ endowed with Life developes itself into an Organism of a type resembling that of its parent; that this organism is the subject of incessant changes, which all tend in the first place to the evolution of its typical form, and subsequently to its maintenance in that form, notwithstanding the antagonism of Chemical and Physical agencies which are continually tending to produce its dis- integration ; but that as its term of existence is prolonged, its conser- vative power declines so as to become less and less able to resist these disintegrating forces, to which it finally succumbs, leaving the organism to be resolved by their agency into the components from which its materials were originally drawn. The history of a living organism, then, is one of incessant change ; f and the conditions of this change are to be ] found partly in the organism itself, and partly in the external influences to ' which it is subjected. . 4. But the Life of any complex organism, such as that of Man, is the * See the Author's Memoir ' On the Mutual Relations of the Vital and Physical Forces' in the Philosophical Transactions for 1850. _ t If change be essential to our idea of Life, it may be asked what is the condition ot a Seed, which may remain unaltered during a period of many centuries vegetating at last, when placed in favourable circumstances, as if it had only ripened the year betore. We can scarcely call it alive, for it is not performing any vital operation. .But it is not dead; for it has undergone no disintegration, and retains its capacity lor living. ine most correct designation of such a state (which can only be maintained under a complete seclusion from disintegrating agencies) seems to bo dormant vitality. Certain Animals may be reduced to it; as the Frog by cold, and the Wheel-animalcule by desiccation Organisms capable of undergoing such a suspension of activity may be kept in a dormant condition so long as disintegrating agencies are excluded; but the very conditions (as heat in the one case, moisture in the other, and both combined in the case of the seed) whose presence is followed by the renewal of active life if the organism has undergone no injurious change, ensure its speedy decay if it be not able to resume its proper vital activity.