We may now return from this excursion through the "Cosmos," to bring its light to bear upon those high-sounding words of Aristotle which, according to Harvey, formed the basis of speculations about the innate heat, the spirits, and the blood, which were handed down by "Scaliger, Fernelius, and others," and affected the views of Harvey himself. Aristotle had written:—
And a little farther on:—
That generative heat which is not elemental fire, but a "body" or "nature" diviner than the lower elements, can be the analogue of nothing else than the celestial ether.
What led Aristotle to so lofty a flight of speculation? He does not tell. One may guess, however, that it may well have been this: that he had found himself obliged not only to deny the identity of the generative heat of the semen with elemental fire, but also to deny the identity with elemental fire even of the glowing sun, as well as of the other planets and the fixed stars; and to maintain that all the heavenly bodies consist of ether. These denials we have read already; they shall presently be commented on. Taking them for granted: now, since the life-giving sun is not elemental fire but ether, would not the life-giving seminal heat, which also is not elemental fire, naturally be the analogue of the ether? "Man and the sun generate man," said Aristotle, in a famous passage.[338] He needed no knowledge of chlorophyll to teach him this. The ether is the element of the sun, moon, stars, and spheres; of it consist the bodies associated with the souls of the living, unalterable, immortal, divine existences of the eternal heaven. To associate a body analogous to this ether with the dormant soul of a living existence—a living existence alterable and mortal as an individual, but one of an immortal race—in the medium which shall maintain that racial immortality by begetting a new individual out of the lower elements—this is a stroke characteristic of the man who declared that "the race of men, and of animals, and of plants, exists forever";[339] the man who assigned to every bloodless animal an analogue of the blood and an analogue of the heart,[340] to the octopus, an analogue of the brain;[341] the man in whose eyes the heavenly bodies were divine living existences running eternal courses and so, we may presume, were analogous in some degree to the living existences of the earth.[342]
Harvey in one of the earlier Exercises of his treatise On Generation had already followed the ancient master's footsteps in this matter. Discoursing of the endless succession of generations the pupil says that this
"makes the race of fowls eternal; since now the chick and now the egg, in an ever-continued series, produce an immortal species out of individuals which fail and perish. We discern, too, that in similar fashion many lower things rival the perpetuity of higher things. And whether or no we say that there is a soul in the egg, it clearly appears from the cycle aforesaid that there underlies this revolution from hen to egg and from egg again to hen, a principle which bestows eternity upon them. That same, according to Aristotle,[343] is analogous to the element of the stars; and it makes parents generate, makes their semen or eggs prolific, and, like Proteus, is ever present."[344]
Let us return now to Harvey's polemic. In it he does not give chapter and verse by which we can properly verify more than a few of his statements of the views of "Scaliger, Fernelius, and others"; but the words of Aristotle which Harvey quotes go far to justify his intimation that the views which he states and combats, as the champion of the circulating blood, are largely derived from those Aristotelian words—whether by misinterpretation, as he roundly but indefinitely declares, or with deliberate modification of doctrine, need not now concern us.
At the very outset of Harvey's discourse about the innate heat, the first doctrine that he reprobates is a striking one, viz.: that the innate heat is one and the same thing with spirits distinguishable from the blood, though not separable from it. Of these spirits he stoutly denies the existence, on the true scientific ground of lack of all evidence from observation in their favor. Our earlier studies of ancient doctrines of respiration have brought before us, as supposed to exist in the blood, spirits variously styled "elemental," "aërial," "nourished by our common and elemental air," "nourished and increased from the thinner part of the blood." We have even read Galen's words of spirits which are "the soul's most immediate instrument," viz.: the "animal spirits" in the brain and nerves. Indeed, during the eighteen centuries between the death of Aristotle and the boyhood of Fernelius and Scaliger, the word "pneuma"—"spirits" or "spirit"—did most varied duties in the service of physicians, philosophers, alchemists, and theologians; and this same word is of great importance in the scriptures.[345] It is noticeable that, although Harvey rejects the doctrine of spirits in the blood, even he himself talks of the blood being itself spirits.[346] This fact, however, should not militate against him or lead to confusion. The word "spirits" being a very comprehensive technical term of his day, he does not refuse to employ it as a label for qualities of the blood after he has denied the very existence of what is properly denoted by the word "spirits." He simply behaves as we behave when we talk of the "sympathetic" nerves, though the theory is exploded which the adjective expresses; or when we speak of "animal cell," well knowing that no proper wall necessarily surrounds the living substance.
Despite the protean forms of the spirits it is not till we have reached Harvey's Exercise On the Innate Heat that we have fallen in with spirits in the blood which, for some of his predecessors, "constitute an innate heat more excellent and more divine, as it were"; nor with "a spirit, another innate heat, of celestial origin and nature." For this treatment of spirits within the blood and of innate heat, as convertible terms, the way may well have been paved by the words in which Aristotle intimates that the generative heat of the semen resides in the spirits therein, i.e., in hot vapor produced within the body of the male and included within the films of foam-bubbles in the semen. Referring to "the so-called heat" the words of Aristotle are: "Yet this is not fire nor any such power, but the spirits included in the semen and in foaminess, and in the spirits the nature which is analogous to the element of the stars."[347] The transition can hardly have been too difficult from the view of Aristotle that in the spirits of the semen is heat which is not elemental fire, to the view combated by Harvey that the spirits of the blood are heat which is not elemental fire.
Aristotle's striking biological doctrine that the generative seminal heat is a "nature which is analogous to the element of the stars" appears to be an obvious source of those seeming fantasies, written down eighteen centuries later, at which Harvey girds when he says: "For what we so commonly would fetch from the stars is born at home." If we use our judgment simply, upon Harvey's statement of their opinions, the men whom he castigates, having strayed from the ancient master's footsteps by making the spirits one and the same with the innate heat instead of the vehicle thereof, next stray still more blindly by identifying this heat, alias these spirits, not with an analogue of the ether, but with a portion of the ether itself. Therefore is it that we read in the words of Harvey's polemic, of "that foreign guest, ethereal heat"; of those spirits "aërial or ethereal, or composed of substance both ethereal and elemental"; of spirits "which draw their origin from heaven" and elicit Harvey's ironical wonder that they "should be nourished by our common and elemental air." Therefore, too, is he able to tell us of that amazing spirit, alias innate heat, which is "a body" and qualified by many imposing adjectives and finally styled "ethereal and sharing in the quintessence." The doctrine of Aristotle that in the semen there are spirits which are the vehicle of generative heat which is analogous to the element of the stars, is a baseless doctrine, but it is a subtle and far-reaching speculation. The doctrine stated and attacked by Harvey that in the blood there are spirits which are the innate heat, which consists as a whole or in part of the element of the stars, is not only a baseless doctrine, as Harvey vigorously shows, but certainly is lame as speculation despite its glittering appeal to the imagination. To make spirits and innate heat convertible terms may pass as but one among many phases of speculation. But to bring down actual ether from heaven to earth, although attempted by eminent thinkers[348] centuries before Scaliger and Fernelius, is to bring chaos into that conception of the universe which requires the "first element" to revolve forever on high, above that lower world which lies beneath the sphere of the moon. To Aristotle such chaos surely would have been abhorrent; indeed, it runs counter to his expressed description of the ether.[349] Moreover, Aristotle's application of the term "analogue" to the generative heat is equivalent to a denial that the generative heat is actually ether; for analogues do frequent service in his doctrines and he explicitly states the analogue of a thing to be something different from the thing itself.[350] What that mysterious analogue of the ether may be with which the generative heat is identified we are not explicitly told, as we are not told what the analogue of the heat may be in bloodless animals. We are left to judge for ourselves after deeper investigation of nature or deeper study of the Aristotelian writings. Had Aristotle been ready to define and describe the body which is more divine than the four lower elements, but is not the first element on high, he probably would not have chosen an analogue as the fittest vehicle for his thought.
According to Harvey the horse of battle of his criticized predecessors was the argument stated by him as follows: "That nothing composed of the elements can work beyond the powers of these, unless it be associated at the same time with another body and that more divine; and ... therefore, that the spirits aforesaid consist in part of the elements, in part of some ethereal and celestial substance."[351] The "spirits aforesaid" are held to be one and the same with the innate heat and reside in the blood. Aristotle had written, we remember: "The virtue or potency of every soul seems to be associated with a body other than the so-called elements and more divine,"[352] viz.: the generative seminal heat, which is not fire but an analogue of the ether. It would seem fairly probable that largely from this doctrine of Aristotle was developed the doctrine about the "powers of the elements" which Harvey sets forth in his polemic. Nothing can be more emphatic than his disagreement with the advocates of this doctrine. "Such persons," he says, "seem to me to have drawn their conclusions ill. For you shall find scarcely any elemental body which, when in action, will not exceed its own proper powers."[353] On the same page with this sweeping statement we find it supported by the following very simple line of thought:—
"All natural bodies present themselves in a double relation, to wit: according as they are reckoned with apart and comprehended within the circuit of their own proper nature, or according as they are the instruments of some nobler and superior authority. For, as to their own proper powers, there is no doubt that all things which are subject to generation and corruption derive their origin from the elements, and work according to the standard thereof. In so far, however, as all things so subject are instruments of a more excellent agent and are regulated thereby, their works do not proceed from their own proper nature but from the rule of that other; and, consequently, they seem to be associated with another and more divine body and to exceed the powers of the elements."[354]
In the very next Exercise, however, that On the Primitive Moisture, the last Exercise of Harvey's treatise On Generation, we come suddenly upon a reason why "the powers of the elements" must have seemed to him something to be treated rather as a convenient form of words than as a serious doctrine, despite his respectful argument just quoted. Speaking of the "primitive moisture," the great observer says that he sees in the hen's egg that out of that "crystalline colliquament," that "simplest body" alone, all the parts of the embryo are made and increased;[355] and proceeds bluntly to question the reality of the elements, "namely, the fire, air, water, and earth of Empedocles and Aristotle; or the salt, sulphur, and mercury of the chemists; or the atoms of Democritus."[356] Harvey says:—
"Therefore, the so-called elements do not exist prior to whatever is generated or arises; but rather are subsequent thereto, being remains rather than origins. Not even Aristotle himself, nor any one else, has ever demonstrated that elements exist separately in nature, or give rise to bodies which consist of parts similar one to another."[357]
Almost immediately after this tug at the foundations of the Aristotelian universe, Harvey brings his treatise On Generation to an end.
The admirable feature of Harvey's brief last-published discussion of the circulating blood is this, that the aged veteran ever strikes vigorous blows for observation, for the use of the senses, in the search for truth. But we have seen already that by his arm, as by another's, the blows are delivered both for better and for worse. Rightly does he drive out of court the spirits "ethereal and elemental" which no man can demonstrate. Wrongly does he discredit the real complexity of that humor, to the eye so simple and crystal-clear, out of which he believes all the diverse parts of the living bird to be developed. In Harvey's present polemic we find no new appeal to nature; he vindicates the justice of his former appeals and maintains with vigor the doctrines already familiar to us, that the blood is the principal part of the body, is itself the innate heat, and is the seat of the soul. This relation of blood and soul he reaffirms very impressively in this, his final public utterance; a most important passage of which, about the presence of the soul in the blood, has been embodied in the chapter on that subject of the present paper.[358]
But evidently the main purpose of his polemical Exercise on the Innate Heat is to cast out of the blood the futile spirits which obscure the real relation of that heat to the circulating blood; and so to defend the thesis best set forth in the following words of his own:—
"In truth, the blood alone is the innate warmth, or the first born psychical heat; as is proved excellently well by our observations of the generation of animals, especially of the chick in the egg; so that it were superfluous to multiply entities....[359] What need, then, is there, say I, of that foreign guest, ethereal heat, since all can be accomplished by the blood, even as by it?"[360]
Harvey has expelled from the blood the mythical spirits which had stood in the way of the direct identification of the blood with the innate heat. But how does he interpret the famous words of Aristotle which he quotes, and declares not to have been "rightly interpreted" by the champions of ethereal spirits? When we seek an answer to this question, we do not find the veteran discoverer at his best. The ancient philosopher surely would have been as much surprised at Harvey's interpretation of his words as at any use of them made by Scaliger or Fernelius. We have seen that Harvey follows up his quotation from Aristotle by promptly applying its language, literally or by paraphrase, to the innate heat and the blood.[361] Emphatic are the words which immediately follow the words of Aristotle. Harvey says:—
"I, too, would say the same, for my part, of the innate heat and the blood, to wit: that it is not fire and does not take its origin from fire, but is associated with another body and that more divine."
This denial he soon repeats, adding the words: "and this is taught excellently well by our observations."
According to Aristotle the soul in the semen is associated with a body diviner than the four lower elements, viz.: the generative heat, an analogue of the element of the stars, which analogue resides in spirits, i.e., in hot vapor within bubbles of seminal foam. In the case of the blood, according to Harvey, it is the heat itself, the innate heat alias the blood, which is associated with "another body and that more divine," and Harvey, having denied the reality of the spirits, uses the word "spirits" as equivalent to "some power" in the blood, which power is "very conspicuous in the nourishing and preserving of the several parts of an animal." In the spirits, so understood, and the blood, dwells the soul; and it is the soul itself which Harvey states to be "a nature analogous [respondens not proportione respondens] to the element of the stars." Even as the word "spirits" has become, in effect, a label for powers of the blood, so the analogue of the ether becomes, in effect, a pious epithet applied to the soul; and only to the soul itself can Harvey have referred as "another body and that more divine." In the next page to the passage now under discussion he says:—
"The blood, therefore, is spirits, because of its extraordinary virtues and powers. It is also celestial, inasmuch as in the spirits aforesaid is lodged a nature, the soul, to wit, which is analogous to the element of the stars; something, that is, analogous to heaven, the instrument of heaven, vicarious of heaven....[362] The heat of the blood is psychical, inasmuch as it is governed in its operations by the soul;[363] it is also celestial, because subservient to heaven; and divine, because the instrument of God, the best and greatest....[364] The lower world, according to Aristotle, is so connected with the courses on high that all its motives and changes seem to take thence their origin and to be governed thence.[365] Truly, in that world which the Greeks called the 'Cosmos' from the beauty of its order,[366] lower and corruptible things are subject to other higher and incorruptible things; but all are beneath the highest, the omnipotent and eternal Creator, and obey Him."[367]
It is obvious that, although Harvey in dealing with the blood does not forego the use of the phrases used by the ancient master in dealing with the semen, nevertheless, the entities recognized by Harvey are not only fewer than those of Aristotle, but are differently disposed within the draperies of Aristotelian language. Harvey's entities are simply the innate heat alias the blood, and the soul which dwells therein; but he sincerely takes himself to be an interpreter of Aristotle's words, as appears a second time from an echo of those words which we meet in an earlier Exercise of Harvey's treatise On Generation. Here, pleading that it is true that the soul is in the blood, Harvey refers to Aristotle by name and immediately says:—
"Indeed, if he is constrained by the truth to acknowledge that there is a soul in an egg, even in a wind-egg;[368] and that in the semen and the blood also there is found something which is divine and analogous to the element of the stars and is vicarious of the omnipotent Creator; and if certain of the modems truly say," etc., etc.[369]
These zealous words show Harvey drawn into statements by no means warranted by the text of Aristotle. We have seen that the Aristotelian heaven was uncreated;[370] and, whatever Harvey in his day may have thought, no "omnipotent Creator" is revealed by more modern study of the Aristotelian philosophy. Whatever inferences Harvey may have drawn from Aristotle's words, Aristotle does not "acknowledge"[371] that the analogue of the ether exists in the blood. Moreover, when in Harvey's Exercise On the Innate Heat that analogue of the element of the stars which Aristotle associated with the soul is identified by Harvey with the soul itself, the change is almost as great as if one should declare that protoplasm is life, instead of styling it with Huxley "the physical basis of life." In a third Exercise of the treatise On Generation, the earliest of the three, Harvey had dealt in a better and more characteristic way with the analogue of the ether; though here, too, his exposition gives no accurate idea of Aristotle's doctrine. In discussing Aristotle's opinion as to how the semen of the cock causes the formation of the embryo Harvey says of Aristotle:—
"Indeed, where he appears to settle and determine with certainty what that may be in whatsoever seed, whether of plants or of animals, which renders the same fruitful, he rejects heat and fire as unfit for the work, but does not give recognition to any similar faculty, nor yet discover in the seed aught suitable for that duty; but is forced to admit something incorporeal, and coming from without, which shall act with understanding and foresight (like art or mind) to form the fœtus, and therein shall establish and order all things to a purpose and for the better. He betakes himself, I say, to something obscure and to us unknown, 'spirits included in the semen and in foaminess, and in the spirits the nature which is analogous to the element of the stars.' But what that may be he has nowhere taught us."[372]
We have found that Aristotle describes "the element of the stars" as a "body,"[373] and that in the passage about the semen which Harvey quotes Aristotle expressly applies the same term, "body," to the analogue of the element of the stars.[374] Yet to this analogue Harvey seems to refer as "something incorporeal" in his last-quoted words, which tend to confound it with soul. Harvey agrees with Aristotle, however, in calling fire a "body";[375] and where in his Exercise On the Innate Heat he extols at some length[376] fire, air and water in motion as flame, wind and flood, he also sets forth how they each claim the title of spirits "by virtue of their movement and perpetual flux,"[377] and says:—
"These three, therefore, in so far as they acquire a certain life, appear to act beyond the powers of the elements and to have a share[378] of another and diviner body; wherefore they were reckoned among the deities by the heathen. For that of which the outcome is some extraordinary work, exceeding the bare faculties of the elements, that same they held to proceed from some diviner agent; as though it were one and the same to act beyond the powers of the elements and to have a share of another and diviner body—diviner, because it does not derive its origin from the elements."[379]
Nowhere but in the third chapter of the second book of Aristotle's treatise On Generation does he refer to the analogue of the ether; and the complete text of this chapter—rugged, here and there, especially in Gaza's Latin translation—may help us perhaps to account for some of Harvey's efforts at exposition.[380] But when these and his reports of his predecessor's doctrines are compared with the words of Aristotle, Harvey and those other biologists of the Renaissance seem like sturdy children reaching forward in the dust, each still clasping a finger of the strong old father who strides among them.
So Harvey denies the doctrine falsely based upon Aristotle's words, the doctrine of the ethereal nature of the innate heat; but he affirms and adopts as his own the Aristotelian distinction between the heat which is sterile and the heat which gives life. This weighty affirmation obliges us who study Harvey to examine this impressive distinction further.[381]
Aristotle says, we remember: "The heat in animals is not fire and does not take its origin from fire." We remember also that Harvey says: "I, too, would say the same, for my part, of the innate heat and the blood, to wit: that it is not fire and does not take its origin from fire." This doctrine is based by both Aristotle and Harvey upon observation; and Aristotle's argument is contained in the passage which Harvey quotes, a passage obscure in the Latin and rugged in the Greek. Briefly, Aristotle's argument is this: Observation shows that fire is sterile, but that the heat of the sun is generative and the heat of animals likewise; therefore, the heat of animals is not fire. Harvey declares that this same conclusion "is taught excellently well" by his observations also—by which he does not expressly say. That Aristotle, in drawing the distinction aforesaid between the heat of fire and the heat of the sun, was playing at hide and seek with a great truth of biology, would soon be apparent to whosoever should take a flourishing green plant from a window warmed by sunshine and try to make the same plant flourish in a dark room warmed by a hidden fire.
At this point let us scan further the words of Aristotle which Harvey has quoted.[337] Aristotle says:[318]—
"For there exists in the semen of all [animals] that which makes their semen generative, the so-called heat. Yet this is not fire, nor any such power, but the spirits[319] included in the semen and in foaminess, and in the spirits the nature which is analogous to the element of the stars.[320] Wherefore fire generates no animal, nor does anything [animal] appear in process of formation in that, whether moist or dry, which is undergoing the action of fire;[321] whereas the heat of the sun and that of animals—not only that [which acts] through the semen,[322] but also, should there occur some excretion of a different nature[323]—even this, too, possesses a life-giving principle. It is patent, then, from such [facts] as these that the heat in animals is not fire and does not take its origin from fire."[324]
In this passage a forcible presentment is made of the sterilizing power of fire, and elsewhere we are told by Aristotle that "only in earth and in water are there animals; there are none in air and in fire."[382] That by the word "fire" we are to understand elemental heat of greater or less intensity is sufficiently shown perhaps by the context. But no doubt will linger if we glance at two lines from another treatise in which, referring expressly to the four elements, Aristotle speaks of earth, water, air, and "what as a matter of custom we call 'fire' but it is not fire; for fire is an excess, a boiling, as it were, of heat."[383]
Harvey, looking askance as he did at the four ancient elements and even bluntly questioning the elementary constitution of matter, felt himself free to reduce the analogue of the ether to a pious epithet, and yet to accept with emphasis the Aristotelian doctrine that the heat of animals "is not fire." At the end of his Exercise On the Primitive Moisture he says: "Nor, lastly, do we find that anything is naturally generated out of fire, as out of something capable of mixture, and the thing is perhaps impossible." Here, however, he is not dealing merely with the generation of living beings, but with a subject deeper yet, the possibility of fire acting as an element at all.[384]
The drift of those sentences which Harvey quotes is lighted up, better perhaps than by any modern commentary, by a passage of Cicero's treatise On the Nature of the Gods, a treatise mentioned by Harvey in his lecture notes,[385] as we have seen. In the orator's lucid Latin we may read what purports to be a quotation from the Greek philosopher Cleanthes, who was a child when Aristotle died in 322 B.C., and who became the second head of the Stoic school, the powerful younger rival of the school of Aristotle. Let us listen to the Roman stoic of 45 or 44 B.C., who is set up by Cicero to quote and expound Cleanthes as follows:—
"Cleanthes says: 'Since the sun is fiery and is nourished by the humors of Ocean (seeing that no fire can last without some kind of food), therefore, the sun must needs be similar either to the fire which we use and apply in our daily life, or to that fire which is contained in the bodies of animate beings. But this fire of ours, which is requisite for the uses of life, is the destroyer and consumer of all things, and wheresoever it has made its way disturbs and dissipates everything; whereas that fire of the body is vital and salutary and by it everything is preserved, nourished, increased, sustained, and endowed with sense.' Cleanthes denies, therefore, that it is doubtful to which of these two fires the sun is similar, seeing that the sun likewise makes all things flourish and ripen, each after its kind. Wherefore, since the sun's fire is similar to those fires which exist in the bodies of animate beings, the sun, too, must be an animate being and, indeed, the rest of the stars that arise in the celestial ardor which is named ether or heaven."[386]
Unlike Aristotle, Cicero's stoic admits that the sun and even the heavenly ether are fire. But we see him to be no less impressed than Aristotle by the difference between the killing heat of flame and the life-giving heat of heaven and of living things. It is interesting to find this difference expressly given as a reason for believing the heavenly bodies to be alive; and one wonders whether this difference may not have had some share in convincing Aristotle that the ether is an element distinct from fire and the other three elements, and more exalted than they. It must be said, however, that Aristotle's habitual use of language about "the heat contained in animals" prepares us ill for the momentous distinction drawn by him between this and elemental heat.
We have found him speaking of "the soul being, as it were, afire" within the heart;[387] and he says also that "the concoction through which nutrition takes place in animals does not go on either in the absence of soul or in the absence of heat, seeing that everything is done by fire."[388] Moreover, there is in his treatise On Soul a passage deserving immediate quotation, no less as a picture of the nascent stage of biological thought, than as showing a phase of Aristotelian doctrine contrasting with the doctrine of the analogue of the ether. He says:—
"By some the nature of fire is held to be quite simply the cause of nutrition and growth; for fire alone among bodies or elements is seen being nourished and growing; wherefore one might assume it to be that which does the work both in plants and in animals. It is, in a way, the contributing cause[389] but not the cause in the simple sense, the soul rather being that; for the growth of fire is limitless, so long as there are combustibles, but in the case of all natural organisms[390] there is a limit to size and growth, and a rationale[391] thereof; these things depending upon the soul, not upon fire, and upon reason rather than upon matter."[392]
Nevertheless, in spite of seeming inconsistencies, we find Aristotle declaring that the heat of fire sterilizes, but the heat of the sun and of animals gives life. Moreover, when he tells us in the passage quoted by Harvey[393] that not only the heat of the sun and of semen, but also the heat of other animal excretions possesses a "life-giving principle," the words appear to suggest not merely generation without sex, but the spontaneous generation either of parasites within the animal body, or of living things in matters cast off from it. We seem to be confronted with the far-reaching thought that there is in the world a life-giving principle by which, when associated with soul, matter is quickened in ways of which sexual generation is only one; and that this principle is generative heat, streaming from the sun or transmitted by the male in coition, and, thereafter, innate in the resulting creature and shared by the humors thereof. The fact must always have been recognized that in some way the existence of living things on earth depends upon the sun. On the other hand, no modern methods fortified Aristotle's intelligence against spontaneous generation, which he accepted as a matter of course and called "automatic generation," even asserting that eels and some other fishes originate in this way.[394] Further statements of his own shall show us now that the sun in its orbit dominates the changes upon and above the earth and is the giver of life, whether imparted by sexual intercourse or otherwise. Then Harvey shall repeat the lesson and thus help us to understand his declaration regarding the innate heat and the blood, to wit: that it "is not fire and does not take its origin from fire."
Aristotle refers to a region beneath the celestial spheres, which region he calls "the first in proximity to the earth," or "the region common to water and air." He says of the events therein:—
These last words are used in a large sense to mean the formation and disintegration of whatever is composed of the four elements.
But the annual circuit of the sun does more than bring to pass the rhythmic changes of the seasons with their effects upon man's environment. To the sun's circuit man owes his life. Aristotle has said to us already: "Man and the sun generate man," in words which have no biological context.[338] He does better when he enumerates among the "causes" of a man these three: his father, the sun, and "the oblique circle," i.e., the ecliptic. These he styles "efficient[397] causes" of man,[398] as we have heard him style "the circle of the sun's course" the "efficient cause" of the mighty changes in inanimate things. We learn in what sense a father is the "efficient cause" of his offspring when Aristotle says: "The female always provides the matter, while the male provides that which fashions it";[399] and when we are told that this matter provided by the female "is quickened by the principle derived from the male, which thus perfects the animal";[400] "the animal" meaning the product of conception. "The body," says Aristotle further, "is from the female, but the soul from the male."[401] For although he says elsewhere that "Genesis is the first obtaining in heat of a share of nutritive soul, and life is the tarrying thereof";[402] although he concedes a share of this lowest kind of soul to wind-eggs, to plants, and to the humblest things which live; nevertheless, he holds that, where the sexes are divided, the indispensable "sensory soul" which distinguishes the animal from the plant is derived from the male parent only.[403] So the seminal fluid and the solar rays are coupled together as "efficient causes" of man; and thus the moving sun is made responsible, by what chain of causation we are not told expressly, for the results of sexual generation.
From this we may turn now to other forms of generation in the light of the following prodigious analogy. Aristotle says:—
"We call 'male' an animal which engenders within another, and 'female' one which engenders within itself; and, therefore, in the case of the universe the earth's nature is held to be female and maternal, while heaven and the sun and other such are called engenderers and fathers."[404]
Next, after these sweeping generalities, let us peruse Aristotle's account of spontaneous generation. He says:—
"Animals and plants arise in earth and in moisture, because in earth there is water and in water there is air,[319] and in all air there is psychical heat; so that in a certain sense all things are full of soul. Therefore, when once inclusion of this[405] has taken place, an individual is quickly formed.[406] Inclusion takes place and a kind of foam-bubble arises, produced by the heating of moisture which has body[407] of its own."[408]
The last expression in this passage evidently means moisture which is charged with earthy matter in solution; for Aristotle says in the same treatise that seawater "has much more body" than drinking-water.[409] Still speaking of spontaneous generation he says a little further on:—
"Whoever would inquire aright should ask: What product in such cases answers to that material principle which in the female is a certain animal excretion,[410] potentially similar to what it came from? That excretion is quickened by the principle derived from the male, which thus perfects the animal. In the present case what should be likened to that excretion, and whence and what is the quickening principle which answers to the principle from the male? Now we must assume that, even in animals which procreate, the heat within the animal[411] separates and concocts, and thus makes out of the nourishment which enters the animal the excretion which is the beginning of the embryo. Such is the case with plants likewise; although in these and in some animals there is no need of the principle imparted by the male, for this they have within and mingled with themselves; whereas in most animals the excretion aforesaid stands in need of that principle. The nourishment of some is water and earth, that of others is derived from water and earth; so that what the heat in animals[412] prepares out of their nourishment, the heat of the season in the circumambient air combines by concoction out of the sea and the earth, and puts together.[413] But so much of the psychical principle as is included or separated within the air[319] constructs and quickens[414] the embryo. In like manner are put together such plants as arise by spontaneous generation."[415]
The doctrine that in sexual generation the semen furnishes soul and generative heat but none of the matter[416] of which the embryo consists, renders logical the view, which Aristotle would seem to hold, that it is soul from the air and generative heat from the sun which in spontaneous generation represent the derivatives from the male.[417] The presence about us of "the psychical principle," thus diffused, may well seem startling to a modern biologist; but we may remind ourselves that in ancient times many believed the soul to be conveyed by the air into even the higher animals; even into man himself, even man's "understanding" reaching him thus.[418] Indeed, not only the words "pneuma" and "spiritus," as we have learned, but also the Greek and Latin words for "soul," viz.: "psyche" and "anima," meant originally simply "breath." Let us recall the words of scripture, which seem so vivid to one who watches the change in a new-born child as the first breath is taken: "And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul."[419]
That the soul enters with the breath is, however, expressly denied by Aristotle. Conceding a share of soul to every living thing he points out quite simply that there are animals which do not breathe at all, to say nothing of plants.[420] Clearly, the doctrine which he rejects would be hard to reconcile with his theory of sexual generation, according to which theory the sensory soul, and in man even the divine intellectual soul, is potential in the semen and imparted thereby to the product of conception.[421] Indeed, there is a chapter of Aristotle's treatise On Soul in which he even seems to argue against the presence of soul in the air, in a polemic directed against those who believe the soul to be "composed of the elements."[422] In this polemic he is the subtle philosopher; but in his statements about generation he seems more the biologist; for in these his thought, if not more ripe, appears to be less concerned with disputation than with phenomena and the interpretation thereof.
The generation of living things is but generation still, whether it be sexual or spontaneous; and the modern student of general physiology may trace further parallels of thought in Aristotle's account of spontaneous generation and in those words of his about the semen which Harvey quotes and we have studied. That living rudiment, spontaneously generated, which consists of a foam-bubble whose film of earth and water was formed by the heat of the sun and includes air charged with generative heat associated with soul—surely that reminds one of the foamy semen, and of "the spirits included in the semen and in foaminess," and of that within the spirits "which makes semen generative, the so-called heat," the "nature which is analogous to the element of the stars," which nature is derived from the male parent and is associated with the soul potential in the semen. In the Greek text of Aristotle one and the same word, "pneuma" is used to express both the air in the foam-bubbles of spontaneous generation, and the vapor in the foam-bubbles of the semen. In translation "pneuma" must be rendered "spirits" in the case of the semen, and the verbal identity is lost which, by reason of the very vagueness of the Greek word, helps to mark the parallelism of thought. It is with pneuma, spirits, that the testicles and breasts are swollen at the advent of puberty,[423] according to Aristotle; and with the presence of pneuma he connects the pleasure of the sexual act.[424] We have found him laying stress upon the fact that "the nature of semen is foamy"—that its "generative medium ἡ γονή is foam": and he tells of the spontaneous generation of certain shellfish in a place where there is "foamy mud."[425] When he obscurely says that in the semen "the pneuma included in the semen and in foaminess"[426] is the vehicle of the generative heat, does not the turn of phrase indicate that Aristotle's thought is ranging far, that he is thinking not only of the foam of the semen but of other widely different kinds of prolific foam as well? Does he not seem to think that, in general, the power of bringing matter to life as a new individual dwells typically in a bubble representing earth, water, and air, and charged with soul and with generative heat, for the presence of which the sun is responsible, heat other than that of elemental fire?[320] It is not fanciful—for Aristotle himself, we remember, has done so incidentally—to connect such speculation with the ancient myth of Aphrodite, the goddess of love, who sprang from the foam which had risen upon the sea, about the immortal genitals of Uranus, which had been severed and cast therein; Uranus being the heavens personified.[427]
Before the time of Aristotle important thinkers had held the heavenly bodies, and even the heavens themselves, to be fire;[428] and we have seen that after his time Cleanthes did the same, simply setting apart the generative fire from the destructive. Aristotle denied that the sun is fire, though he could not have denied that its radiant generative heat produces no different sensation from that of sterile fire kindled upon earth. He did not identify the sun's heat with ether, the "body on high," though he styled the heat of the semen a "body" analogous to the ether. How then did Aristotle obtain heat from the ethereal sun? The point is crucial and he met it; but in so doing he revealed a very weak place in his towering fabric of speculation. In his treatise On Heaven, speaking of the heavenly bodies, he says:—
"The heat and light from these arise from the friction which the air undergoes by reason of their course. For it is the nature of motion to fire even wood and stone and steel."
He then speaks of projectiles, and says:—
"These, then, are heated because borne onward in air which becomes fire from the shock of the motion. But each of the bodies on high is borne onward in its sphere, so that they are not fired; while the air, being beneath the sphere of the circling body,[429] is heated of necessity as this [body] is borne onward, and mainly where the sun is set in place. Therefore, when the sun approaches and rises and is above us, heat is generated. Be it said, then, of the heavenly bodies, that neither are they fiery nor are they borne on in fire."[430]
In his Meteorology Aristotle boldly says: "The sun, which is held to be especially hot, appears white, but not to be like fire."[431]
Hardy thinker as he is, however, Aristotle nowhere undertakes to tell how the heat of friction between the air and the circling "first element" on high becomes generative, as opposed to the heat of friction between the air and a projectile composed of the lower elements. As to this the Aristotle who deals with the heavens does not strike hands with Aristotle the biologist; nor is light thrown by its author on the Aristotelian passage quoted by Harvey, in which alone does the generative heat of animals figure as "the nature which is analogous to the elements of the stars";[432] nor yet does the Aristotelian dictum that "Man and the sun generate man"[338] remain other than a great truth which awaits elucidation.
More than nineteen centuries after Aristotle's death Harvey published the following, in his treatise On Generation:—
"Thus the sun and man, that is, the sun through man as an instrument, generate. In the same way the Father of all and the cock generate the egg and the chick derived from the egg; namely, by means of the perpetual approach and withdrawal of the sun, which by the will of divine authority, or by fate if you choose, serves for the generation of all things.
"Our conclusion, then, is that the male, although a prior and more important efficient cause than the female, is only an instrumental efficient cause; that he, no less than the female, receives his fecundity or generative power from the approaching sun; and that, accordingly, the art and providence which we discern in his works proceed not from himself but from God."[433]
Two pages farther on Harvey says, again:—
"In fact, what the cock confers upon the egg to make it no longer a wind-egg but prolific, is the same that is bestowed by the summer fervor of the sun upon vegetable fruits, that they may reach maturity, and their seeds, fecundity; and the same that imparts fecundity to beings that arise spontaneously[434] and that produces caterpillars out of worms, chrysalides out of caterpillars, out of chrysalides, butterflies, flies, bees, and the rest."[435]
In a later Exercise of the same treatise Harvey says:—
"As I have said, the product of conception in viviparous creatures is analogous to the seed and fruit of plants; as also is the egg in the ovipara; in creatures which come into existence spontaneously, the worm;[436] or some bubble of confined moisture[437] pregnant with vital heat. In all of the foregoing exists that which is the same in all, that in virtue of which they are called with truth seeds; that, namely, out of which and by which, preëxisting as matter, artificer, and instrument, every animal is in the first instance made and comes into existence."[438]
Despite emphatic denials of Aristotelian doctrine which Harvey freely makes in his treatise On Generation, the Aristotelian flavor of the foregoing passages is obvious. It is not easy to make out from Harvey's writings the exact nature of his views as to spontaneous generation. He sometimes seems to assume the truth thereof; but it is by no means certain that he believed in it in the same simple sense in which it had been accepted by Aristotle.[439] Nothing, however, can be clearer than this: that, though for Harvey the "innate heat" is not ethereal spirits nor even an analogue of the ether, but is simply identical with the living blood; nevertheless, for him as emphatically as for Aristotle the "heat in animals" which "is not fire and does not take its origin from fire," derives its origin from the solar ray.
To Harvey, the lifelong thinker upon the meaning of the circulation, the prodigious history of generation was but continued in the history of the blood, with which he had identified the "innate heat" and which he saw appear and live, before all other parts, in the minute first rudiment of the embryo. We have seen him pondering the cycle wherein unending life is transmitted from egg to fowl and from fowl to egg beneath the sun's life-giving rays. So now shall we see him pondering a cycle of life wherein, from generation to generation, the circulating blood takes over and exercises the generative powers of the semen from which it is derived, and transmits them in turn to the semen evolved out of itself. He says:—
"Further, since we have just seen the study of the semen to be so difficult; that is to say, the way in which the structure of the body is built up by the semen with foresight, art, and divine intelligence; why should we not equally admire the excellent nature of the blood, and make the same reflections upon it as upon the semen? Especially since the semen itself is made of blood,[440] as is proved in the case of the egg; and since the whole body is seen not only to take origin from the blood as from a generative part, but also to owe its preservation to the same."[441]
To this same theme Harvey returns in his Exercise On the Innate Heat near the end of his treatise On Generation, saying:—
"The blood, too, acts in like manner above the powers of the elements, because, when it has come into existence as the first generated part and the innate heat, as is brought to pass in the semen and spirits, the blood constructs the remaining parts of the whole body in order; and does so with the highest foresight and understanding,[442] acting to a certain end and as though by some use of reason.[443] Surely the blood does not accomplish these things because it is composed of elements and draws its origin from fire, but because by the grace of plastic power and vegetative soul it is made the first generated heat and the immediate and fitting instrument of life."[444]