THE INNATE HEAT NOT DERIVED FROM ELEMENTAL FIRE
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:--
"Of these the efficient[395] cause and ruler and first origin is
the circle of the sun's course, which, it is evident, produces
separation and combination by its approach or withdrawal and is
the cause of generation and corruption."[396]
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]