his natural history, since in dealing with physiological questions he
always seems to have in mind the body as a whole and seldom pauses for
any detailed investigation of a particular part. The physiological
views of Aristotle were far from being fully accepted even by the
generation which followed him. There was already growing up a school
of physiologists whose work culminated five centuries later in that of
Galen, where we find quite other views of the bodily functions. It is
these views which we may take as more typical of the bases of Greek
physiology (see p. 66).
In much of the Aristotelian material that we have discussed we have
seen the development of a class of interests very foreign to those
of the modern biologist, in whose work the general discussion of the
ultimate nature and origin of life seldom plays a large part. The
business of the modern biologist is mainly with vital phenomena as he
encounters them and he is not concerned with the deeper philosophical
problems. The man of science considers a part of the Universe where the
philosopher makes it his business to regard the whole. With Aristotle
this modern scientific process of taking a part of the sensible
Universe, such as a particular group of animals or the particular
action of a particular organ, and considering it in and by and for
itself without reference to other things, had not yet fully emerged.
Philosophy and science are still inextricably linked and there is no
clear demarcation between them.
This is at least his theoretical view. But besides being a philosopher
by choice he was a supreme naturalist by his natural endowments and he
cannot suppress his love for nature and his capacity for observation.
We see Aristotle the naturalist at his greatest as a direct observer
or when reasoning directly about the observations that he has made.
When he disregards his own observations and begins to erect theories
on the observations or the views of others, he becomes weaker and less
comprehensible.
§ 3. _After Aristotle_
All Aristotle’s surviving biological works refer primarily to the
animal creation. His work on plants is lost or rather has survived
as the merest corrupted fragment. We are fortunate, however, in the
possession of a couple of complete works by his pupil and successor
Theophrastus (372-287), which may not only be taken to represent the
Aristotelian attitude towards the plant world, but also give us an
inkling of the general state of biological science in the generation
which succeeded the master.
These treatises of Theophrastus are in many respects the most complete
and orderly of all ancient biological works that have reached our time.
They give an idea of the kind of interest that the working scientist
of that day could develop when inspired rather by the genius of a
great teacher than by the power of his own thoughts. Theophrastus
is a pedestrian where Aristotle is a creature of wings, he is in a
relation to the master of the same order that the morphologists of the
second half of the nineteenth century were to Darwin. For a couple
of generations after the appearance of the _Origin of Species_ in
1859 the industry and ability of naturalists all over the world were
occupied in working out in detail the structure and mode of life of
living things on the basis of the Evolutionary philosophy. Nearly
all the work on morphology and much of that on physiology since his
time might be treated as a commentary on the works of Darwin. These
volumes of Theophrastus give the same impression. They represent the
remains—alas, almost the only biological remains—of a school working
under the impulse of a great idea and spurred by the memory of a great
teacher. As such they afford a parallel to much scientific work of our
own day, produced by men without genius save that provided by a vision
and a hope and an ideal. Of such men it is impossible to write as of
Aristotle. Their lives are summed up by their actual achievement, and
since Theophrastus is an orderly writer whose works have descended to
us in good state, he is a very suitable instance of the actual standard
of achievement of ancient biology. ‘Without vision the people perish’
and the very breath of life of science is drawn, and can only be drawn,
from that very small band of prophets who from time to time, during the
ages, have provided the great generalizations and the great ideals. In
this light let us examine the work of Theophrastus.
In the absence of any adequate system of classification, almost all
botany until the seventeenth century consisted mainly of descriptions
of species. To describe accurately a leaf or a root in the language
in ordinary use would often take pages. Modern botanists have
invented an elaborate terminology which, however hideous to eye and
ear, has the crowning merit of helping to abbreviate scientific
literature. Botanical writers previous to the seventeenth century were
substantially without this special mode of expression. It is partly to
this lack that we owe the persistent attempts throughout the centuries
to represent plants pictorially in herbals, manuscript and printed, and
thus the possibility of an adequate history of plant illustration.
Theophrastus seems to have felt acutely the need of botanical terms,
and there are cases in which he seeks to give a special technical
meaning to words in more or less current use. Among such words are
_carpos_ = fruit, _pericarpion_ = seed vessel = pericarp, and _metra_,
the word used by him for the central core of any stem whether formed of
wood, pith, or other substance. It is from the usage of Theophrastus
that the exact definition of fruit and pericarp has come down to
us.[64] We may easily discern also the purpose for which he introduces
into botany the term _metra_, a word meaning primarily the _womb_, and
the vacancy in the Greek language which it was made to fill. ‘_Metra_,’
he says, ‘is that which is in the middle of the wood, being third in
order from the bark and [thus] like to the marrow in bones. Some call
it the _heart_ (καρδίαν), others the _inside_ (ἐντεριώνην), yet others
call only the innermost part of the metra itself the heart, while
others again call this _marrow_.’[65] He is thus inventing a word to
cover all the different kinds of core and importing it from another
study. This is the method of modern scientific nomenclature which
hardly existed for botanists even as late as the sixteenth century of
our era. The real foundations of our modern nomenclature were laid in
the later sixteenth and in the seventeenth century by Cesalpino and
Joachim Jung.
[64] It is possible that Theophrastus derived the word pericarp from
Aristotle. Cp. _De anima_, ii. 1, 412ᵇ 2. In the passage τὸ φύλλον
περικαρπίου σκέπασμα, τὸ δὲ περικάρπιον καρποῦ, in the _De anima_ the
word does not, however, seem to have the full technical force that
Theophrastus gives to it.
[65] _Historia plantarum_, i. 2, vi.
Theophrastus understood the value of developmental study, a conception
derived from his master. ‘A plant’, he says, ‘has power of germination
in all its parts, for it has life in them all, wherefore we should
regard them not for what they are but for what they are becoming.’[66]
The various modes of plant reproduction are correctly distinguished
in a way that passes beyond the only surviving earlier treatise
that deals in detail with the subject, the Hippocratic work _On
generation_. ‘The manner of generation of trees and plants are these:
spontaneous, from a seed, from a root, from a piece torn off, from a
branch or twig, from the trunk itself, or from pieces of the wood cut
up small.’[67] The marvel of generation must have awakened admiration
from a very early date. We have already seen it occupying a more
ancient author, and it had also been one of the chief pre-occupations
of Aristotle. It is thus not remarkable that the process should impress
Theophrastus, who has left on record his views on the formation of the
plant from the seed.
[66] _Ibid._ i. 1, iv.
[67] _Historia plantarum_, ii. 1, i.
‘Some germinate, root and leaves, from the same
point, some separately from either end of the seed.
Thus wheat, barley, spelt, and all such cereals
[germinate] from either end, corresponding to the
position [of the seed] in the ear, the root from the
stout lower part, the shoot from the upper; but the
two, root and stem, form a single continuous whole.
The bean and other leguminous plants are not so, but
in them root and stem are from the same point, namely,
their place of attachment to the pod, where, it is
plain, they have their origin. In some cases there is
a process, as in beans, chick peas, and especially
lupines, from which the root grows downward, the leaf
and stem upward.... In certain trees the bud first
germinates within the seed, and, as it increases in
size, the seeds split—all such seeds are, as it were,
in two halves; again, all those of leguminous plants
have plainly two lobes and are double—and then the
root is immediately thrust out. But in cereals, the
seeds being in one piece, this does not happen, but the
root grows a little before [the shoot].
‘Barley and wheat come up monophyllous, but peas,
beans, and chick peas polyphyllous. All leguminous
plants have a single woody root, from which grow
slender side roots ... but wheat, barley, and the other
cereals have numerous slender roots by which they are
matted together.... There is a contrast between these
two kinds; the leguminous plants have a single root and
have many side-growths above from the [single] stem
... while the cereals have many roots and send up many
shoots, but these have no side-shoots.’[68]
There can be no doubt that here is a piece of minute observation on the
behaviour of germinating seeds. The distinction between dicotyledons
and monocotyledons is accurately set forth, though the stress is
laid not so much on the cotyledonous character of the seed as on the
relation of root and shoot. In the dicotyledons root and shoot are
represented as springing from the same point, and in monocotyledons
from opposite poles in the seed.
No further effective work was done on the germinating seed until
the invention of the microscope, and the appearance of the work of
Highmore (1613-85),[69] and the much more searching investigations of
Malpighi (1628-94)[70] and Grew (1641-1712)[71] after the middle of the
seventeenth century. The observations of Theophrastus are, however, so
accurate, so lucid, and so complete that they might well be used as
legends for the plates of these writers two thousand years after him.
[68] _Historia plantarum_, viii. 1, i.
[69] Nathaniel Highmore, _A History of Generation_, London, 1651.
[70] Marcello Malpighi, _Anatome plantarum_, London, 1675.
[71] Nehemiah Grew, _Anatomy of Vegetables begun_, London, 1672.
Much has been written as to the knowledge of the sex of plants among
the ancients. It may be stated that of the sexual elements of the
flower no ancient writer had any clear idea. Nevertheless, sex is often
attributed to plants, and the simile of the Loves of Plants enters
into works of the poets. Plants are frequently described as male and
female in ancient biological writings also, and Pliny goes so far as
to say that some students considered that all herbs and trees were
sexual.[72] Yet when such passages can be tested it will be found that
these so-called males and females are usually different species. In
a few cases a sterile variety is described as the male and a fertile
as the female. In a small residuum of cases diœcious plants or flowers
are regarded as male and female, but with no real comprehension of the
sexual nature of the flowers. There remain the palms, in which the
knowledge of plant sex had advanced a trifle farther. ‘With dates’,
says Theophrastus, ‘the males should be brought to the females; for the
males make the fruit persist and ripen, and this some call by analogy
_to use the wild fig_ (ὀλυνθάζειν).[73] The process is thus: when the
male is in flower they at once cut off the spathe with the flower
and shake the bloom, with its flower and dust, over the fruit of the
female, and, if it is thus treated, it retains the fruit and does not
shed it.’[74] The fertilizing character of the spathe of the male date
palm was familiar in Babylon from a very early date. It is recorded by
Herodotus[75] and is represented by a frequent symbol on the Assyrian
monuments.
[72] Pliny, _Naturalis historia_, xiii. 4.
[73] The curious word ὀλυνθάζειν, here translated _to use the wild
fig_, is from ὄλυνθος, a kind of wild fig which seldom ripens. The
special meaning here given to the word is explained in another work
of Theophrastus, _De causis plantarum_, ii. 9, xv. After describing
caprification in figs, he says τὸ δὲ ἐπὶ τῶν φοινίκων συμβαῖνον οὐ
ταὐτὸν μέν, ἔχει δέ τινα ὁμοιότητα τούτω δι’ ὁ καλοῦσιν ὀλυνθάζειν
αὐτούς. ‘The same thing is not done with dates, but something analogous
to it, whence this is called ὀλυνθάζειν’.
[74] _Historia plantarum_, ii. 8, iv.
[75] Herodotus i. 193.
The comparison of the fertilization of the date palm to the use of the
wild fig refers to the practice of Caprification. Theophrastus tells
us that there are certain trees, the fig among them, which are apt
to shed their fruit prematurely. To remedy this ‘the device adopted
is caprification. Gall-insects come out of the wild figs which are
hanging there, eat the tops of the cultivated figs, and so make them
swell’.[76] These gall-insects ‘are engendered from the seeds’.[77]
Theophrastus distinguished between the process as applied to the fig
and the date, observing that ‘in both [fig and date] the male aids
the female—for they call the fruit-bearing [palm] _female_—but whilst
in the one there is a union of the two sexes, in the other things are
different’.[78]
[76] _Historia plantarum_, ii. 8, i.
[77] _Ibid._ ii. 8, ii.
[78] _Historia plantarum_, ii. 8, iv.
Theophrastus was not very successful in distinguishing the nature
of the primary elements of plants, though he was able to separate
root, stem, leaf, stipule, and flower on morphological as well
as to a limited extent on physiological grounds. For the root he
adopts the familiar definition, the only one possible before the
rise of chemistry, that it ‘is that by which the plant draws up
nourishment’,[79] a description that applies to the account given by
the pre-Aristotelian author of the work περὶ γονῆς, _On generation_.
But Theophrastus shows by many examples that he is capable of following
out morphological homologies. Thus he knows that the ivy regularly puts
forth roots from the shoots between the leaves, by means of which it
gets hold of trees and walls,[80] that the mistletoe will not sprout
except on the bark of living trees into which it strikes its roots,
and that the very peculiar formation of the mangrove tree is to be
explained by the fact that ‘this plant sends out roots from the shoots
till it has hold on the ground and roots again: and so there comes to
be a continuous circle of roots round the tree, not connected with
the main stem, but at a distance from it’.[81] He does not succeed,
however, in distinguishing the real nature of such structures as bulbs,
rhizomes, and tubers, but regards them all as roots. Nor is he more
successful in his discussion of the nature of stems. As to leaves, he
is more definite and satisfactory, though wholly in the dark as to
their function; he is quite clear that the pinnate leaf of the rowan
tree, for instance, is a leaf and not a branch.
[79] _Ibid._ i. 1, ix.
[80] _Ibid._ iii. 18, x.
[81] _De causis plantarum_, ii. 23.
[Illustration: Fig. 8. THEOPHRASTUS
From VILLA ALBANI
Copy (second century A. D.?) of earlier work]
Notwithstanding his lack of insight as to the nature of sex in flowers,
he attains to an approximately correct idea of the relation of flower
and fruit. Some plants, he says, ‘have [the flower] around the fruit
itself as vine and olive; [the flowers] of the latter, when they drop,
look as though they had a hole through them, and this is taken for a
sign that it has blossomed well; for if [the flower] is burnt up or
sodden, the fruit falls with it, and so it does not become pierced.
Most flowers have the fruit case in the middle, or it may be the flower
is on the top of the pericarp as in pomegranate, apple, pear, plum,
and myrtle ... for these have their seeds below the flower.... In
some cases again the flower is on top of the seeds themselves as in
... all thistle-like plants’.[82] Thus Theophrastus has succeeded in
distinguishing between the hypogynous, perigynous, and epigynous types
of flower, and has almost come to regard its relation to the fruit as
the essential floral element.
[82] _Historia plantarum_, i. 13, iii.
Theophrastus has a perfectly clear idea of plant distribution as
dependent on soil and climate, and at times seems to be on the point
of passing from a statement of climatic distribution into one of real
geographical regions. The general question of plant distribution long
remained at, if it did not recede from, the position where he left
it. The usefulness of the manuscript and early printed herbals in the
West was for centuries marred by the retention of plant descriptions
prepared for the Greek East and Latin South, and these works were saved
from complete ineffectiveness only by an occasional appeal to nature.
With the death of Theophrastus about 287 B. C. pure biological science
substantially disappears from the Greek world, and we get the same
type of deterioration that is later encountered in other scientific
departments. Science ceases to have the motive of the desire to know,
and becomes an applied study, subservient to the practical arts. It
is an attitude from which in the end applied science itself must
suffer also. Yet the centuries that follow were not without biological
writers of very great ability. In the medical school of Alexandria
anatomy and physiology became placed on a firm basis from about 300
B. C., but always in the position subordinate to medicine that they
have since occupied. Two great names of that school, Herophilus
and Erasistratus, we must consider elsewhere.[83] Their works have
disappeared and we have the merest fragments of them. In the last
pre-Christian and the first two post-Christian centuries, however,
there were several writers, portions of whose works have survived and
are of great biological importance. Among them we include Crateuas, a
botanical writer and illustrator, who greatly developed, if he did not
actually introduce, the method of representing plants systematically by
illustration rather than by description. This method, important still,
was even more important when there was no proper system of botanical
nomenclature. Crateuas by his paintings of plants, copies of which have
not improbably descended to our time, began a tradition which, fixed
about the fifth century, remained almost rigid until the rediscovery
of nature in the sixteenth. He was physician to Mithridates VI Eupator
(120-63 B. C.), but his work was well known and appreciated at Rome,
which became the place of resort for Greek talent.[84]
[83] See the companion chapter on _Greek Medicine_.
[84] The works of Crateuas have recently been printed by M. Wellmann
as an appendix to the text of Dioscorides, _De re medica_, 3 vols.,
Berlin, 1906-17. The source and fate of his plant drawings are
discussed in the same author’s _Krateuas_, Berlin, 1897.
Celsus, who flourished about 20 B. C., wrote an excellent work on
medicine, but gives all too little glimpse of anatomy and physiology.
Rufus of Ephesus, however, in the next century practised dissection
of apes and other animals. He described the decussation of the optic
nerves and the capsule of the crystalline lens, and gave the first
clear description that has survived of the structure of the eye. He
regarded the nerves as originating from the brain, and distinguished
between nerves of motion and of sensation. He described the oviduct of
the sheep and rightly held that life was possible without the spleen.
The second Christian century brings us two writers who, while
scientifically inconsiderable, acted as the main carriers of such
tradition of Greek biology as reached the Middle Ages, Pliny and
Dioscorides. Pliny (A. D. 23-79), though a Latin, owes almost
everything of value in his encyclopaedia to Greek writings. In his
_Natural History_ we have a collection of current views on the nature,
origin, and uses of plants and animals such as we might expect from an
intelligent, industrious, and honest member of the landed class who
was devoid of critical or special scientific skill. Scientifically the
work is contemptible, but it demands mention in any study of the legacy
of Greece, since it was, for centuries, a main conduit of the ancient
teaching and observations on natural history. Read throughout the ages,
alike in the darkest as in the more enlightened periods, copied and
recopied, translated, commented on, extracted and abridged, a large
part of Pliny’s work has gradually passed into folk-keeping, so that
through its agency the gipsy fortune-teller of to-day is still reciting
garbled versions of the formulae of Aristotle and Hippocrates of two
and a half millennia ago.
The fate of Dioscorides (flourished A. D. 60) has been not dissimilar.
His work _On Materia Medica_ consists of a series of short accounts
of plants, arranged almost without reference to the nature of the
plants themselves, but quite invaluable for its terse and striking
descriptions which often include habits and habitats. Its history has
shown it to be one of the most influential botanical treatises ever
penned. It provided most of the little botanical knowledge that reached
the Middle Ages. It furnished the chief stimulus to botanical research
at the time of the Renaissance. It has decided the general form of
every modern pharmacopœia. It has practically determined modern plant
nomenclature both popular and scientific.
Translated into nearly every language from Anglo-Saxon and Provençal
to Persian and Hebrew, appearing both abstracted and in full in
innumerable beautifully illuminated manuscripts, some of which are
still among the fairest treasures of the great national libraries,
Dioscorides, the drug-monger, appealed to scholasticized minds for
centuries. The frequency with which fragments of him are encountered in
papyri shows how popular his work was in Egypt in the third and fourth
centuries. One of the earliest datable Greek codices in existence is a
glorious volume of Dioscorides written in capitals,[85] thought worthy
to form a wedding gift for a lady who was the daughter of one Roman
emperor and the betrothed of a second.[86] The illustrations of this
fifth century manuscript are a very valuable monument for the history
of art and the chief adornment of what was once the Royal Library at
Vienna[87] (figs. 9-10). Illustrated Latin translations of Dioscorides
were in use in the time of Cassiodorus (490-585). A work based on it,
similarly illustrated, but bearing the name of Apuleius, is among
the most frequent of mediaeval botanical documents and the earliest
surviving specimen is almost contemporary with Cassiodorus himself.[88]
After the revival of learning Dioscorides continued to attract an
immense amount of philological and botanical ability, and scores of
editions of his works, many of them nobly illustrated, poured out of
the presses of the sixteenth and seventeenth centuries.
[85] The manuscript in question is Med. Graec. 1 at what was the Royal
Library at Vienna. It is known as the _Constantinopolitanus_. After the
war it was taken to St. Mark’s at Venice, but either has been or is
about to be restored to Vienna. A facsimile of this grand manuscript
was published by Sijthoff, Leyden, 1906.
[86] The lady in question was Juliana Anicia, daughter of Anicius
Olybrius, Emperor of the West in 472, and his wife Placidia, daughter
of Valentinian III. Juliana was betrothed in 479 by the Eastern Emperor
Zeno to Theodoric the Ostrogoth, but was married, probably in 487 when
the manuscript was presented to her, to Areobindus, a high military
officer under the Byzantine Emperor Anastasius.