BOOK IV. CHAPTER I. Life. "First then, if any one think that the secrets of nature remain shut up, as it were with the seal of God, and by some divine mandate interdicted to human wisdom, we shall address ourselves to remove this weak and jealous notion; and, relying on simple truth, shall bring the inquiry to this issue, not only to silence the howl of superstition, but to draw religion herself to our side." BACON. WHETHER in a theoretical or practical point of view, the animating principle is the most important problem that ever engaged the attention of mankind; for it connects all that is profound and fascinating in physics, with the science of preserving health and prolonging life. Never can the healing art take its appropriate rank among the exact sciences until the cause of vital force and animal motion is distinguished from the operations which it produces; but must remain, as in all the ages that are past, a mere collection of empirical rules. If it be true that every deviation from health is immediately connected with some derangement of the vital principle, there cannot be a doubt, that a clear comprehension H H of what it is, and of the laws by which it operates, would do more to meliorate the condition of mankind, than all the systems that have been invented from the age of Hippocrates to the present time; because it would lead, not only to a certain method of curing diseases, but, what would be of vastly greater consequence, the theory of life would become intelligible to all; and its chief glory would be the prevention rather than the cure of maladies. The whole object of medical science is to regulate the forces of life-to increase them when and where they are deficient-to restrain them when excessive-and to restore their natural balance when deranged. But how can we know the best means of maintaining the functions of life in a healthy state, while ignorant of the physical cause on which they all depend? How is it possible to counteract with certainty, those involuntary movements that constitute tetanus, hydrophobia, and other forms of convulsive disease, without knowing the cause of muscular contraction in a state of health? How can we adopt the best treatment of fever, inflammation, and the various species of malarious affections, without comprehending the true theory of animal heat, and the specific office which it performs in the economy of life? Why are so many diseases pronounced incurable, though attended with no organic lesion, and ranked among the opprobria medicorum, but that men are ignorant of what causes the heart to beat, the stomach to digest, the brain to think, the nerves to feel, and our active limbs to move? The true panacea, or elixir of life, must not be sought in specifics and nostrums, but in a clear and definite knowledge of the mode in which the organizing principle operates in the different functions of life. Were it not that all the phenomena of nature are linked together as parts of one great whole, it would be of far higher importance to know the cause of vital, than that of planetary motion. Nor was it ever intended by Infinite Wisdom and Goodness, that knowledge so essential to the happiness of our race should remain a sealed book. Life is the problem of problems, the solution of which would clear up a thousand other mysteries, and banish innumerable errors from the pages of science. And it may be asserted with confidence, that whoever is without faith in the power of well-directed efforts to resolve it, will never accomplish much towards enlarging the empire of man over the numerous evils by which he is surrounded. A complete knowledge of this subject would do more to elevate the condition of mankind, than the power of transmuting the baser metals into gold, or even charcoal into the precious diamond; for all the riches of the earth are not to be compared with health. But, unfortunately for the best interests of the world, an impression has long prevailed, that the animating principle is something beyond the powers of the human mind to comprehend. That such dogmas should have been inculcated by the founders of narrow creeds, and individuals interested in keeping the people in ignorance, is not to be wondered at; for in all ages of the world, the empire of imposture has been founded on pretended mysteries, and upheld by ignorance. It is, however, melancholy to reflect, that philosophers have given countenance to this prejudice. Enslaved by ancient errors, even the wise Socrates is said to have thought it dangerous, unprofitable, and not acceptable to the gods, for men to pry into the hidden mechanism of nature. And in an article on Life, contained in his Philosophical Dictionary, Voltaire, a professed champion of free inquiry, asserts, that "the cause of animal motion, like that which determines all things to a common centre, and the needle to the pole, is the secret of the Deity." The general adoption of this opinion by the instructors of mankind, has done immense injury to the cause of science, by discouraging the efforts of genius to press forward into the undiscovered regions of truth; while it has fostered ignorance, indolence, and every description of quackery. If there be any primary and efficient cause of vital force, it must be either a portion of the air we breathe, or of the |