Harvey then discusses at some length the Aristotelian and scholastic views of the word “spirit” and “vital principle,” and in the end arrives at the conclusion that “the blood, by reason of its admirable properties and powers, is ’spirit.’ It is also celestial; for nature, the soul, that which answers to the essence of the stars is the inmate of the spirit, in other words, it is something analogous to heaven, the instrument of heaven, vicarious of heaven.... The blood, too, is the animal heat in so far namely as it is governed in its actions by the soul; for it is celestial as subservient to heaven, and divine because it is the instrument of God the great and good.”
Harvey next attacks the doctrine of those who maintained that nothing composed of the elements can show powers superior to the forces exercised by these unless they at the same time partake of some other and more divine body, and on this ground conceive the spirits they evoke as constituted partly of the elements, partly of a certain ethereal and celestial substance. He observes very pertinently in opposition to such a train of reasoning: “In the first place you will scarcely find any elementary body which in acting does not exceed its proper powers; air and water, the winds and the ocean, when they waft navies to either India and round this globe, and often by opposite courses, when they grind, bake, dig, pump, saw timber, sustain fire, support some things, overwhelm others, and suffice for an infinite variety of other and most admirable offices—who shall say that they do not surpass the power of the elements? In like manner what does not fire accomplish? In the kitchen, in the furnace, in the laboratory, softening, hardening, melting, subliming, changing, in an infinite variety of ways! What shall we say of it when we see iron itself produced by its agency?—iron ‘that breaks the stubborn soil and shakes the earth with war’! Iron that in the magnet (to which Thales therefore ascribed a soul) attracts other iron, ’subdues all other things and seeks besides I know not what inane,’ as Pliny says; for the steel needle only rubbed with the lodestone still steadily points to the great cardinal points; and when our clocks constantly indicate the hours of the day and night, shall we not admit that all of these partake of something else, and that of a more divine nature than the elements? And if in the domain and rule of nature so many excellent operations are daily effected, surpassing the powers of the things themselves, what shall we not think possible within the pale and regimen of nature, of which all art is but imitation? And if, as ministers of man, they effect such admirable ends, what I ask may we not expect of them, when they are instruments in the hand of God?
“We must therefore make the distinction and say, that whilst no primary agent or prime efficient produces effects beyond its powers, every instrumental agent may exceed its own proper powers in action; for it acts not merely by its own virtue but by the virtue of a superior efficient....
“Since the blood acts, then, with forces superior to the forces of the elements, and exerts its influence through these forces or virtues and is the instrument of the Great Workman, no one can ever sufficiently extol its admirable, its divine faculties.
“In the first place and especially, it is possessed by a soul which is not only vegetative, but sensitive and motive also. It penetrates everywhere and is ubiquitous; abstracted, the soul or the life too is gone, so that the blood does not seem to differ in any respect from the soul or the life itself (anima); at all events it is to be regarded as the substance whose act is the soul or the life. Such, I say, is the soul, which is neither wholly corporeal nor yet wholly incorporeal; which is derived in part from abroad and is partly produced at home; which in one way is part of the body, but in another is the beginning and cause of all that is contained in the animal body, viz., nutrition, sense, and motion, and consequently of life and death alike; for whatever is nourished, is itself vivified, and vice versâ. In like manner that which is abundantly nourished increases; what is not sufficiently supplied shrinks; what is perfectly nourished preserves its health; what is not perfectly nourished falls into disease. The blood therefore, even as the soul, is to be regarded as the cause and author of youth and old age, of sleep and waking, and also of respiration. All the more and especially as the first instrument in natural things contains the internal moving cause within itself. It therefore comes to the same thing, whether we say that the soul and the blood, or the blood with the soul, or the soul with the blood performs all the acts in the animal organism.” A lame and impotent conclusion which does not advance our knowledge, though perhaps it was the most plausible that could be drawn from the premisses at Harvey’s command. Indeed he was himself dissatisfied with his conception of the vital principle, for in another essay after a discussion to show that the egg is not the product of the body of the hen, but is a result of the vital principle, he turns away from the subject with evident relief to more profitable subjects, and with the words “Leaving points that are doubtful and disquisitions bearing upon the general question, we now approach more definite and obvious matters.”
The ideas then prevalent in physical science led him in like manner to spend much time and thought upon the unprofitable subject of the primigenial moisture, and with these speculations the treatise on development comes to an abrupt end.
The whole essay is an interesting one. It shows us the range of Harvey’s mind filled with the knowledge of ancient philosophy, but animated by the experimental spirit of modern science. All that the work contains of observation and experiment is valuable, for Harvey had made use of his uncommon opportunities to acquire a knowledge, such as is usually possessed only by huntsmen and gamekeepers, and has very rarely been attained by a man of science. Harvey’s knowledge, as shown in this treatise, may be compared to that shown by Darwin in his “Variation of Animals and Plants under Domestication.” Harvey tries to explain his observations in the terms of an existing philosophy, while Darwin uses his facts to establish an original hypothesis of his own. We have so completely outlived the age of the schoolmen that it is difficult for us to recognise the bondage endured by so great a mind as Harvey’s until we consider it in the light of Darwin’s work. Then we recognise that the theoretical disquisitions in the treatises on development are not so foreign to the true nature of Harvey as they appear to be at first sight. They are in reality an illustration of the profound influence of the prevalent thought of a period upon every contemporary mind, and show that the most thoughtful and original are not always the least affected.
We thus take leave of one of the master minds of the seventeenth century. Harvey’s osteological lecture has not yet been found, and many of his investigations in comparative anatomy are still wanting. But there is a possibility that his papers and books were only dispersed, and were not destroyed at the pillage of his lodgings in Whitehall. Some of the wreckage is still cast up from time to time, and we may hope that more may yet be found. So recently as 1888 Dr. Norman Moore recognised thirty-five lines of Harvey’s handwriting on a blank page at the end of the British Museum copy of Goulston’s edition of Galen’s “Opuscula Varia.” Here, as in all the other manuscripts, the peculiarities of Harvey’s writing are too distinct to leave any doubt of the authorship. Every fragment of his work is interesting, and even in these few lines we seem to learn his opinion of artificial exterior elevation as opposed to the genuine exaltation of worth or learning, for against a passage in which Galen prefers learning to rank, Harvey has written “wooden leggs.” A fitting testimony from one who, though he had spent the greater part of his life at court, was yet the foremost thinker of his age.
FINIS.