BIOLOGICAL SCIENCES
It is usually assumed that the biological sciences have developed in
comparatively recent years and that above all nearly 500 years ago in
the fifteenth century there could be no question of any developments
that would be of any serious significance in the history of science.
The word biology itself is only about a hundred years old and very
often it is assumed that human interest in departments of knowledge
begins with the naming of them. A period, however, that saw such
magnificent work in the physical sciences and especially such a
revolution of thought by means of observation as came through
Copernicus' theory, was not likely to neglect the biological sciences
entirely. As a matter of fact, biology, taking the word in its
broadest sense, made some magnificent strides at this time. Perhaps no
period until our own witnessed such significant advances in every
department of the biological sciences.
It is often said that the people of the Middle Ages had very little
interest in the world around them. Indeed, surprise is often expressed
that they should not have occupied themselves more with the wonderful
book of nature lying so invitingly open before them and given
themselves more to nature study. Some have even ventured to seek the
reason and have thought that they found in it an exaggeration of
interest in another world than this, and mediaeval lack of interest in
natural truth has been attributed to over-occupation with the
supernatural. Those who dare to think, however, that the people of the
Middle Ages were not interested in nature know nothing at all of the
great writers of that time. They are profoundly ignorant of the broad
interests of those whom they so lightly criticise. Dante is full of
nature study. More than any modern poet, with perhaps one or two
exceptions, he has used his {361} knowledge of nature and of science
to illustrate his meaning in many passages of his poetry. One needs
but turn to the "Divine Comedy" almost anywhere to prove this. In his
"Treatment of Nature in Dante." Professor Oscar Kuhns of Wesleyan
University has demonstrated this beyond all doubt.
Three voluminous encyclopaedias of knowledge, including many of the
wonderful facts of nature, were compiled in the thirteenth century.
Such men as Albertus Magnus, who has many volumes of scientific
writing on natural subjects and who made collections and observations
of all kinds, Roger Bacon, who has so many almost incredible
anticipations of modern knowledge, and Thomas Aquinas, who used the
facts of nature as known in his time for the basis of his philosophy
quite as Aristotle did long before, all were enthusiastic nature
students. They did not know many things which the modern schoolboy can
easily learn, for we have accumulated a great deal of information;
since not a little that they thought they knew was wrong,--but that
has been true in every period of the world's history of science and
even our own will not escape that inevitable law, but they knew ever
so much more than is usually thought and what they knew was much more
significant for real scientific progress than any but special students
of their works have any idea of.
It will not be surprising, then, to find that there were magnificent
foundations laid in the biological sciences in Columbus' Century, and
that indeed the work of this period represents some of the most
important fundamental truths in these sciences. Anatomy, for instance,
received a development during the Renaissance period that made it an
independent scientific department. Men began to think again for
themselves and make their own observations in the first half of the
century. It is rather interesting to see the details that were added
to the previous knowledge of anatomy, for these demonstrate the fact
that they were observing accurately; A few examples will suffice to
make this clear.
Achillini noticed the _ductus choledochus_, the duct leading from the
liver into the duodenum, and described the ilio-caecal valves.
Berengar of Carpi corrected a number of mistakes that had existed in
Mondino's _Anathomia_, the text-book {362} which had been most used
since the beginning of the fourteenth century, and he discovered the
foramina in the sphenoid bone. He will have, perhaps, still more of
interest for our time, because he was the first to describe the
vermiform appendix. He was also the first apparently to call attention
to the fact that the thorax in men and the pelvis in women are wider
in each case proportionately than in the other sex, and that roughly,
while the feminine form is conical, the masculine is an inverted cone.
Canani added much to the description of the muscles and was the first
to notice the presence of valves in veins, discovering them in the
_vena azygos_. Gabriele Zerbi noted the oblique and the circular
muscles of the stomach and described the puncta lachrymalia, the
ligamenta uteri and other anatomical details which had escaped
description previously. His book on anatomy divided the bones and
muscles and blood vessels into different chapters, and order was
beginning to come out of the confusion that had existed because of the
too-generalized teaching before.
It is of the anatomists of this time that Puschmann in his "History of
Medical Education" says, "The Italian anatomists had the habit of
making the dissections of bodies for themselves, and it is for this
reason that all the great anatomical discoveries of the time come from
Italy. The anatomical schools of that country were the best in the
world. All the greatest anatomists of the sixteenth century received
their education there, and among the masters of the Italian schools
are to be found the greatest names of which the science of anatomy can
boast." Neuberger in his "Handbook of the History of Medicine"
[Footnote 30] says, "The Italian professors, incited by the brilliant
example of 'Mondino,' surpassed all the other anatomists of the world
because they did not disdain to take in their own hands the anatomical
scalpel, and it is for that reason that at this time anatomy in Italy
was cultivated with greater breadth of vision than elsewhere. The
Italian anatomists initiated at the end of the fifteenth century the
most famous period in the history of the art of dissection {363} and
became the teachers to the physicians of the whole world."
[Footnote 30: Neuberger u. Pagel: _"Handbuch der Geschichte der
Medicin";_ Jena, 1903, Vol. II, p. 23.]
Martinotti in his "The Teaching of Anatomy in Bologna Before the
Nineteenth Century" [Footnote 31] gives a very good idea of the
thoroughly scientific spirit of their investigations and their ardent
curiosity with regard to anatomical details, as these may be gathered
from the commentaries of Berengar of Carpi. He says, for instance,
"Let no one think that by word of mouth alone or the study of books,
this science of anatomy" [he calls it discipline] "can be learned. For
this the sight and touch are absolutely necessary." "Nor can any real
knowledge of the members of the human body be obtained from a single
dissection, for this a number of dissections are required." He himself
says in suggesting with true scholarly spirit how little he knows in
spite of his opportunities, in order that others may be encouraged to
take as many opportunities as possible, "how many hundreds of cadavers
have I not dissected." This expression is sometimes said to be an
exaggeration, but it is in accord with the whole trend of Berengar's
method of study. A dissection in the old time did not mean a complete
study of the anatomy of the body by anatomical methods, but any
opening of the body, in order to determine a particular point or to
study any special part, was called an anatomy or dissection. Berengar
insists frequently that a number of preparations and sections of the
same viscus should be studied. He confesses that he had sectioned more
than 100 cadavers in order to determine a question in brain anatomy
and yet was not satisfied.
[Footnote 31: G. Martinotti: _L'Insegnamento dell' Anatomia in
Bologna Prima del Secolo XIX;_ Bologna, 1911.]
The interests of the artists of the Renaissance in painting not merely
the surface of things, but giving an idea of what they actually were,
led to a great development of curiosity as to the constitution of
human beings. Not a single great artist of the Renaissance failed to
make dissections for himself, and the greater the artist, the more
dissections, as a rule, we know he made. Michelangelo dissected
portions at least of more than 100 bodies, and Leonardo da Vinci
probably did even much more than that. He proposed at one time to
write a {364} textbook of anatomy. Ordinarily, it would be presumed
that any such proposition from an artist could scarcely be taken
seriously in the sense of a scientific text-book to represent real
contributions to anatomy as a science, though it might, of course, be
valuable for artists. In recent years, however, the republication of
the sketches of his dissections shows that Leonardo da Vinci might
have written a very wonderful textbook of anatomy and that his plates
are still valuable for the study of professed anatomists.
William Hunter declared that "Leonardo was the greatest anatomist of
this period," and, as altogether we have some 750 separate sketches of
dissections which he had actually studied, some idea of how much he
accomplished can be obtained. These sketches represent not merely the
muscles and the skeleton, though they give these very well and
especially suggest their functions very completely, but they also
contain sketches of all the viscera and even cross-sections of the
brain at different planes. This book alone, without anything further,
would give Leonardo a distinguished place in the history of physiology
as well as of anatomy.
With all this in mind, it is amusing to know the impression rather
prevalent among even educated people that there was Church opposition
to dissection at this time, and to have such books as President
White's "Warfare of Science with Theology" represent Vesalius a
generation after this as dissecting in fear and trembling because of
the danger he was incurring from the violation of ecclesiastical laws
against dissection. No such laws were ever in existence, and
dissection for scientific and artistic purposes was apparently much
better provided for than it is even in our time, and above all much
better cared for by the ecclesiastical authorities who might have
hampered it so much, than it was in the English-speaking countries two
or three generations ago, when ardent students of anatomy had either
to "resurrect" bodies themselves or buy them--as many of them
did--from "resurrectionists," with all the abuses connected with this
practice, in order to secure anatomical material.
The supreme development of anatomy in Columbus' Century came with
Vesalius. After exhibiting his trend of mind {365} towards scientific
and especially biological studies as a boy by the dissection of small
animals, the suggestion for which had come to him from the study of
Albertus Magnus' books, Vesalius went to Paris in order to find
opportunities for anatomical study; but while profiting not a little
there, he was rather disappointed because of the lack of facilities.
The jealousy of his teacher, Sylvius, which he aroused, made his work
still more difficult, so he went down to Italy, where he knew that he
could secure material for dissection and opportunities for study.
There, before he was twenty-five, they made him professor of anatomy
at the University of Padua, and he had the opportunity to write his
great text-book on anatomy, the _"De Fabrica Humani Corporis,"_ which
has remained a classic down to our day.
It would be rather difficult to enumerate all the discoveries that we
owe to Vesalius. He well deserves the name of the Father of Modern
Anatomy. Practically all of his productive life comes in Columbus'
Century, and he illustrates how thorough the scientific men of the
time were in their modes of thinking and ways of observation. Details
that might have been expected to escape him are described most
clearly. He was the first to point out that nerves penetrated muscles
and to suggest the physiological function that they performed of
bringing about contraction. He discovered the little blood vessels
that enter bones, the nutrient arteries, but still more definitely
described the nutrition of bones through the periosteum and its rich
blood supply. He added greatly to the knowledge of the time as regards
the anatomy of the abdominal wall and of the large organs of the
abdominal cavity, especially the stomach and the liver. His
descriptions of the sex organs are far in advance of all that his
predecessors had known, and here his anatomical knowledge also became
of value for suggestions in physiology,--the two cognate sciences
were, as might be expected, developing together. Vesalius described
the heart completely and suggested its mechanism, and yet could not
get away from Galen's declaration that the blood passes through the
septum of the heart. His description of blood vessels and their inner
and outer coat shows how carefully his observations were made. He
declared {366} afterwards that he was led to make these investigations
by the memory of his dissection of the bladders with which he used to
play as a boy and which he found to consist of several coats.
There is scarcely a department of anatomy on which Vesalius' name is
not stamped deeply. He devoted great care, for instance, to the
examination of the brain, emphasized the distinction between the gray
and white matter, described the corpus callosum, the septum lucidum,
the pineal gland and the corpora quadrigemina.
Two at least of Vesalius' disciples and assistants in teaching deserve
to be named in the great development of anatomy that came at this
time. One of them is Realdus Columbus, to whom we owe the discovery of
the circulation of the blood in the lungs, and the other, Fallopius,
whose name is familiar from its attachment to important structures in
the body which he first described. Columbus we shall have more to say
of under physiology, for the circulation of the blood was an important
contribution to that science. Columbus' work was done at Rome, whither
he was invited by the Popes to teach at the Papal Medical School, and
where his directions and demonstrations were attended by cardinals,
archbishops, and distinguished ecclesiastics. He had been Vesalius'
prosector at Padua and had succeeded him at Bologna, and then was
invited to Rome. He wrote a great text-book of anatomy, which was
dedicated to Pope Paul IV, and it was one of the treasures of the
Renaissance both because of the development of anatomy which it
represents, and its value as one of the early beautifully printed and
illustrated books of the medicine of this time.
Fallopius, the gifted pupil of Vesalius, of whom Haeser, the modern
historian of medicine, has said that he was "one of the most important
of the many-sided physicians of the sixteenth century," followed his
master's work, corrected some details of it and added many new facts.
We are not quite sure of the time of his birth, but he was probably
less than thirty, perhaps only twenty-five, when he became professor
of anatomy at Ferrara. He subsequently occupied the chair of anatomy
at Pisa, and later of anatomy and surgery at Padua. He {367} added
much to what was known before about the internal ear and described in
detail the tympanum and its relations to the osseous ring in which it
is situated. He also described minutely the circular and oval windows
and their communication with the vestibule and cochlea. He was the
first to point out the connection between the mastoid cells and the
middle ear. His description of the lachrymal passages in the eye was a
marked advance on those of his predecessors, and he also gave a
detailed account of the ethmoid bone and its cells in the nose. His
contributions to the anatomy of the bones and muscles were very
valuable. It was in myology particularly that he corrected Vesalius.
He studied the organs of generation in both sexes, and his description
of the canal or tube which leads from the ovary to the uterus attached
his name to the structure. Another discovery, the little canal through
which the facial nerve passes after leaving the auditory, is also
called after him the _aquaeductus Fallopii._
Puschmann in his "History of Medical Education" says of Fallopius (p.
297): "He furnished valuable information upon the development of the
bones and teeth, described the petrous bone more accurately, enriched
myology by admirable descriptions of the muscles of the external ear,
of the face, of the palate and of the tongue, made explicit statements
upon the anastomotic connections of certain blood-vessels--for
instance, of the carotid and vertebral arteries--and discovered the
nervus trochlearis. He instituted accurate investigations upon
particular parts of the organ of hearing and of the eye, by which he
was able to give fuller information upon the _ligamentum ciliare,_ the
_tunica hyaloidea,_ the lens, and other anatomical points."
As great, if not greater, than either as an anatomist was Eustachius,
to whom we owe a series of important discoveries. He studied
particularly the renal system and the head. His name is enshrined in
the Eustachian tube named after him. It has been said that after
Eustachius' time very little was added to our knowledge of the gross
anatomy of the teeth. He also made important discoveries in brain
anatomy. Unfortunately his text-book was never finished, and the
beautiful illustrations, the first copperplates for an anatomical work
ever made, were {368} not published in his lifetime. They were
faithfully preserved, however, in the Library of the Vatican, for,
like Columbus, he was a professor at the Papal Medical School in Rome,
and were published at the beginning of the eighteenth century by
Lancisi, himself, another Papal physician.
Another of the distinguished anatomists of the time was Aranzius, who
was the Professor of Anatomy in the Papal University of Bologna for
some thirty-two years just after the close of our period, having
received his training, however, in our century. He gave the first
correct account of the anatomy of the foetus and was the first to show
that the muscles of the eye do not arise from the dura mater but from
the margin of the optic cavity. He confirmed Columbus' views with
regard to the course of the blood in passing from the left to the
right side of the heart, and made a number of discoveries in the
anatomy of the brain. To him we owe the term _hippocampus_, and he
described the fourth ventricle very accurately, calling it the cistern
of the cerebellum.
The scientific development of physiology followed immediately, as
might be expected, on that of anatomy. Indeed, Vesalius deserves
almost as much credit for what he did for physiology as for his
researches in anatomy. The functions of bones, muscles and organs
were, as we have said, carefully discussed in connection with the
descriptions of their form, location and relations to other organs.
Probably the best way to present the advance made in physiology at
this time is to review the important steps of progress toward that
greatest generalization in modern physiology, the circulation of the
blood. Much more had been known of it before this time than is usually
thought, and probably even the ancients, especially in Greece, had
more than a hint of it. Before Columbus' Century closed, the discovery
of the pulmonary circulation was an accomplished fact, and there was
more than an inkling of the existence of the general circulation. The
full description of this was not made until afterwards, but it was not
long delayed, and it came from a man who belongs to our time. It did
not receive that thorough scientific statement which was to make it a
fundamental principle in the biological science of the time until
Harvey's day, nor indeed for some {369} time after Harvey's thoroughly
scientific description and demonstration. [Footnote 32]
[Footnote 32: How clearly Rabelais understood the function of the
circulation, though he did not properly appreciate its physiological
anatomy, may be readily seen from his famous passage on the
circulation, in which he talks about the blood as "the rivulet of
gold which is received with such joy by all the organs because it is
their sole restorative." A portion of the passage is worth while
quoting because it represents a popularization of the scientific
knowledge of the time. Rabelais was writing not for physicians nor
even medical students, but for the educated general public of the
time. He said:
"The Spleen draweth from the _Blood_ its terrestrial parts,
_viz._, the Grounds, Lees or thick Substance settled in the bottom
thereof, which you term _Melancholy;_ the Bottle of the Gall
subtracts from thence all the superfluous _Choler:_ whence it is
brought to another Shop or Workhouse to be yet better purified and
refined, that is the Heart, which by its agitation of Diastolick
and Systolick Motions so neatly subtiliseth and inflames it, that
in the _right-side_ Ventricle it is brought to Perfection and
through the Veins is sent to all the Members; each Parcel of the
Body draws it then into itself, and after it's own fashion, is
cherished and alimented by it: Feet, Hands, Thighs, Arms, Eyes,
Ears, Back, Breast, yea, all; and thus it is that who before were
_Lenders,_ now become _Debtors,_ The Heart doth in its _left-side_
Ventricle so thinnify the Blood that it thereby obtains the name
of Spiritual; which being sent through the Arteries to all the
members of the Body, serveth to warm and winnow or fan the other
Blood which runneth through the Veins; The Lights never cease with
its Lappets and Bellows to cool and refresh it; in Acknowledgment
of which good the Heart through the Arterial Vein imparts unto it
the choicest of it's Blood: At last it is made so fine and subtle
within the _Rete Mirabile,_ that thereafter those _Animal Spirits_
are framed and composed of it; by means whereof the Imagination,
Discourse, Judgment, Resolution, Deliberation, Ratiocination, and
Memory have their Rise, Actings and Operations."]
Harvey himself indeed has acknowledged his indebtedness to these men
of preceding generations, and any fair-minded review of the subject
makes it clear that there was a gradual progress towards this
all-important generalization for several generations, and not that
sudden discovery which is sometimes thought to have taken place. In
1546 Servetus, who had been Professor of Anatomy at Paris, but who had
a tendency to dabble in theology that subsequently proved unfortunate
for him, for, as will be recalled, he was burnt to death by Calvin
{370} at Geneva in 1553, sent to Curio, who was teaching anatomy at
Padua, a manuscript copy of his _"Restitutio Christianismi,"_ "The
Restoration of Christendom," in which he described completely the
circulation of the blood in the lungs.
Because Servetus' description first appeared in a theological work, it
has sometimes seemed to commentators that his expressions were
scarcely more than accidental and that it was only by chance that he
reached such a generalization. To say this, however, is to ignore
Servetus' career. He was an investigator of a thoroughly scientific
spirit, living in a time when discoveries, particularly in the
biological sciences, were being made all round him, and he had made
many dissections, had taught anatomy at the University of Paris and
was exactly in the most appropriate position to make such a new
discovery. He had done some distinguished work in botany, he had
suggested some modifications in pharmacology which met with violent
opposition, but have since been approved, and like so many of the men
of the Renaissance he had "taken all knowledge for his province" with
a wonderful degree of success. Unfortunately he invaded theology and
then got into trouble. He had to fly from Paris, though probably the
prosecution of him was due not a little to the enemies created by his
uncompromising spirit in the controversy over the use of syrups. He
was protected by the Archbishop of Vienne, who had him as physician
for a dozen of years, and it was Calvin who denounced him to the Roman
authorities in such a way that even the friendly Archbishop could no
longer protect him. He was allowed to escape from jail by connivance,
went to Geneva and there met his sad fate.
It may not be true, as has been said, that by putting him to death
Calvin put back the development of physiology for three-quarters of a
century until Harvey's time, but undoubtedly Servetus' death was a
very unfortunate incident for science.
Just about this same time a series of discoveries in Italy led up to
the thought of the existence of a circulation of the blood in lungs
and body. Already in the first edition of his great text-book of
anatomy in 1543, Vesalius had expressed doubts {371} with regard to
the Galenic doctrine that the blood passed through the septum of the
heart from one ventricle to another, and these doubts he emphasized in
the second edition. In 1547 Cananus, Professor of Anatomy at Ferrara,
observed the valves in the veins, and these are said to have been
described even before this, though the doctrine of their existence and
function was not generally accepted in science until after the more
complete description made by Fabricius of Aquapendente, who was born
in our century but did his important work afterwards. Columbus, who
was teaching anatomy at the Papal University of the Sapienza in Rome,
was even more complete and explicit in his description of the
pulmonary circulation than had been Servetus. The question as to
whether he knew of Servetus' discovery has never been absolutely
settled, though there seems very little likelihood of it. Apparently
the one possibility is that a copy of the edition of the _"Restitutio
Christianismi"_ which was burned with its unfortunate author, may have
been spared and found its way to Rome. Rome is indeed the least likely
place for such a book to have wandered, and only two copies of that
first edition are definitely known to have escaped. Of these Columbus
could have known nothing. Harvey himself, to quote Professor Foster in
his "History of Physiology," spoke of Columbus with respect as of a
great authority.
Columbus' work has sometimes been minimized in Western Europe,
especially by the English, apparently in the fear lest recognition for
him should lessen Harvey's glory. Harvey himself, however, quotes
Columbus as an authority in his work on the circulation, and the
Italian anatomist, who had been Vesalius' assistant, was undoubtedly a
great teacher, investigator, dissector, experimenter, observer and
writer with regard to a number of phases of medical science. He was
the first to insist on demonstrations of living animals as valuable in
the teaching of medicine. He declared that one could learn more about
the functions of the body from the dissection of a single dog than
from feeling the pulse for hours and merely studying Galen. He made
demonstrations on living animals and was constantly engaged in trying
to find out function as well as anatomical details. A number of
workers in the medical {372} sciences toward the end of Columbus'
Century were making experiments of various kinds on living and dead
animals in order to develop physiology. Eustachius studied the kidneys
experimentally, and the sensory functions were investigated very
carefully and with the true scientific spirit.
The completion of the discovery of the circulation of the blood came
in the person of Caesalpinus, who had received all of his education in
Columbus' Century. Anyone who reads his description of the systemic
circulation cannot fail to recognize that he really understood it. His
discovery did not impress his generation as did that of Harvey in the
next generation, nor did he understand so thoroughly the significance
of his discovery. The Italians, however, have quite rightly insisted
on vindicating for him the merit of having discovered the circulation
of the blood, and some of them have even suggested that Harvey learned
of it from him, but nothing can dim Harvey's glory as a great trained
observer and original genius, who appreciated thoroughly the nature of
the revolution that his discovery would work in the medical sciences.
Harvey himself would have been the first to deprecate the lessening of
the glory that was due to his predecessors or to his great teachers in
Italy, one of whom, Fabricius da Aquapendente, belongs partly to our
century. Indeed, in his book on the circulation, Harvey has given more
credit to his predecessors than many of his ardent English advocates
are prone to do in the modern time.
Professor Foster in his "Lectures on the History of Physiology During
the Sixteenth, Seventeenth and Eighteenth Centuries," which were
delivered as the Lane Lectures in San Francisco, and some of them also
at Johns Hopkins, concedes Caesalpinus' priority of description. He
says (page 33):
"He thus appears to have grasped the important truth, hidden, it
would seem, from all before him, that the heart, at its systole,
discharges its contents into the aorta (and pulmonary artery), and
at its diastole receives blood from the vena cava (and pulmonary
vein).
"Again in his 'Medical Questions,' he seems to have grasped the
facts of the flow from the arteries to the veins, and of flow along
the veins to the heart"
{373}
On page 35 of the same work Professor Foster says: "We must,
therefore, admit that Caesalpinus had not only clearly grasped the
pulmonary circulation, but had also laid hold of the systemic
circulation; he recognized that the flow of blood to the tissues took
place by the arteries and by the arteries alone, and that the return
of the blood from the tissues took place by the veins and not by the
arteries."
Foster is prone to make little of Caesalpinus as a man of
book-learning rather than experimental or observational knowledge and
as a scholarly writer rather than a scientific discoverer. It must not
be forgotten, however, that Caesalpinus, besides being a great
anatomist, is one of the most important contributors to the botany of
this time. He was the director of the first botanical garden regularly
established in Italy, that at Pisa, which still exists, and he is
called by Linnaeus the first true systematic botanist. His work on
plants distributed more than 1500 plants into fifteen classes
distinguished by their fruits.
Every detail of the circulation is thus seen to have been understood,
and Professor Foster has quoted the passages from Caesalpinus' books
which make the necessity for such an admission very clear. The
Italians have always claimed the discovery of the circulation for
Caesalpinus, and the Southern nations of Europe generally have been
inclined to favor that claim, though the Germans and English have
refused to admit that even Caesalpinus' description, with all its
clearness of detail, can be taken to mean that he understood the new
doctrine that he thus was teaching. Besides, it is pointed out that
Caesalpinus' new doctrines met with very little response and indeed
scarcely any notice from his contemporaries. It must not be forgotten,
however, that Harvey himself hesitated for some dozen years to publish
his demonstration of the circulation of the blood, and there is good
reason to believe that while he presented his views to his class in
1616 and wrote his treatise in 1619, he delayed its publication until
1628 and was even then apprehensive lest its appearance make "mankind
his enemy." It is not surprising, then, in the light of this
recognized attitude of the scientific mind of the time that
Caesalpinus' declarations of half a century before should have been
passed {374} over by scientists without proper recognition of their
significance.
Any account of the development of the biological sciences at this time
would be quite incomplete without the great story of the botanists who
laid the broad, deep foundation of their favorite science during this
century. The first distinguished name among them is that of Leonardo
da Vinci, the story of whose work in botany seems almost incredible
until the actual notes of his observations are before one. While
Leonardo has been thought of always as a painter and only recently has
the idea of his greatness as a scientist become generally known, he
deserves eminently to be classed as one of the greatest of scientific
geniuses. It was in the biological sciences that he did his most
wonderful work. He knew the anatomy of men and animals very well and
studied whole series of questions touching living beings. He did work
in botany, palaeontology, zoology, physiology, so that Duval did not
hesitate to speak of him in the _Revue Scientifique_ [Footnote 33] as
A Biologist of the Fifteenth Century. He made special observations on
flying, on swimming, on the saving of life in shipwreck, on the
mechanics of joints, on horse movement, so that he anticipated what we
have learned by the camera. His special contribution to physiology was
that certain acts of the nervous system are reflex, that is, without
requiring attention from the higher centres.
[Footnote 33: December 7, 1889.]
His studies in color are among the most interesting done up to his
time. These were not merely taken up from the physical standpoint but
especially from the physiological, and his theory of color vision
still attracts attention. He studied sound and made many valuable
observations once more physiological as well as physical. His most
interesting scientific conclusion was doubtless that with regard to
fossils. Having met with them deep below the surface of the earth, he
declared that they were not there by accident nor by any
incompleteness of creation, but that they represented living things
which had been covered up. He even suggested that marine fossils
pointed to the fact that the sea had at some time covered this spot
where {375} the fossils were found, though this was now far from water
and well above its level.
Some of his information with regard to botany was far ahead of his
time. He not only knew that the rings seen in the wood of the trunk of
a tree represent its age, one ring for each year, but he also knew how
to deduce from the differing thickness of the various rings the
particular kind of season and how favorable it was for growth. In
Italy moisture represents to a great extent the most important element
in a favorable year for plant growth. Leonardo seems to have shown by
the story of certain years in the past that when moisture was abundant
the rings of the trees were thicker than they had been in other years.
He pointed out, too, that the core of the trunk of a tree, the heart
of the wood as we call it, was not in the centre of the tree as a
rule, but always a little to one side because the tree had more
sunlight and heat on one side and grew more in that direction. He
pointed out too that when a tree is injured an abundance of sap is
carried to that spot in order to bring about repair, and that these
processes of repair always make a super-abundance of tissue, as if to
overstrengthen a weaker part--hence the irregularities that are
likely to exist on a tree where injuries have been inflicted. The
sketches of dissections of flowers found in his notebooks show how
well he anticipated many methods of study and details of knowledge in
botany supposed to be much more modern. They have proved as great a
surprise as his anatomical plates.
The professional botanists of this period have been very thoroughly
reviewed by Professor Edward Lee Greene, Professor of Botany at the
Catholic University and Associate in Botany in the United States
National Museum, in his "Landmarks of Botanical History," which forms
part of Volume LIV in the Smithsonian Miscellaneous Collections. He
has called attention particularly to the work of the great German
Fathers of modern botany during the late fifteenth and early sixteenth
centuries. There are five of them who deserve a prominent place in the
history of botany. Otho Brunfelsius (1464-1534), Leonhardus Fuchsius
(1506-1566), Hieronymus Tragus (1498-1554), Euricius Cordus
(1486-1535) and Valerius Cordus (1515-1544). The four first named
represent two distinct {376} kinds of botanical work. Brunfels and
Fuchs busy themselves almost wholly with medical botany. Their one
idea was to describe plants that could be used in medicine or make
special additions to the diet. Most of their plant descriptions are
copied from older authors, some of them even the Greeks, but for
practical purposes they sought to render the identification of medical
plants more easy and certain by supplying pictures of them. There had
been botanical pictures before but they were miserable as a rule, and
both Brunfels and Fuchs greatly improved the representations. As
Greene says "these two might worthily have been styled Fathers of
Plant Iconography."
Books of botany must have been popular before this and indeed it was
probably because of the ready sale of such works that Brunfels and
Fuchs took up their elaboration of them. Their large picture books now
made it possible for all sorts and conditions of men, lettered and
illiterate, to identify some hundreds of useful plants; a thing which
had never happened in the world before that day. They added little to
scientific botany, however, but fortunately other men, Tragus and
Valerius Cordus, laid serious scientific foundations for the true
science of botany. Neither of these men wished to popularize botany so
much as to make it possible for plants to be so described as to be
readily identifiable by description. As Greene says "on Cordus' part
it is unmistakable that there is a deliberate plan of creating a new
phytography. Therefore and by study of the men and their books I think
we shall perceive that in the Germany of the first half of the
sixteenth century there were two fathers of plant iconography and two
fathers of descriptive botany."
Greene can scarcely say too much of the work of young Cordus. He says
(page 272): "To understand the exalted character of this genius it is
only necessary to canvass what the youth had also attained to along
other and different lines at the same time.
"In field work in Germany--for botany alone--not to speak of geology
and mineralogy, in both of which he was, for his time, an expert--he
had wrought out more results than had his older contemporaries,
Brunfelsius, Tragus, and Fuchsius combined. In his repeated journeys
to the great forests and {377} wildest mountain districts, it is
estimated that he discovered several hundred new plants. Sprengel
has given the Linnaean names of some twenty-five of these new
discoveries of Cordus; and that is perhaps double or treble the
number of novelties gathered in by the whole three above named; and
they both were men of longer life and more or less extensive
travel."
Greene re-echoes the praise of a contemporary in terms which show us
that this young man, who lived less than thirty years, had all the
qualities of a modern successful scientific investigator. Indeed that
contemporary description is worth while having near one as a catalogue
of qualities of the men who in every age succeed in science as a rule.
It comes from Riffius' Preface to Cordus' "Annotations on
Dioscorides":
"To the best possible education of an intellect naturally keen,
there was united in him that happy temperament to which nothing is
impossible, or even difficult of attainment. To these gifts he added
a truly marvellous industry and assiduity in research; and above
all, a most wonderfully retentive memory for everything he either
saw in nature or read in books. In this he so greatly excelled as to
be able to carry in mind in their entirety descriptions of things
which he had not seen but was looking to find; thus having the
descriptions always available whenever occasion called for the use
of them."
Conrad Gesner at Zurich declared that the four books of Cordus are
"truly extraordinary because of the accuracy with which the plants are
described. A century and a half later, Tournefort named Valerius
Cordus as having been the first of all men to excel in plant
description. Haller, the distinguished botanist and historian in
Linnaeus' time, credited Valerius Cordus with having been "the first
to teach independence of the poor descriptions of the ancients and to
describe plants anew." Greene says of him: "One sees that in all his
descriptions the same attention is given to the morphology and also to
the life history of the plant in as far as this is known to him. In
his practice of describing each species, both morphologically and
biologically, he is a herald of our late nineteenth and early
twentieth century writers who now that we have the microscope give
life histories with minuteness of detail before impossible."
{378}
Evidently Columbus' period gave birth to men as great in the
investigation of plants and as ardent in their desires to get the last
details of truth as were the geographers and the navigators of the
time to reach the ends of the earth and be able to map it out. There
was a great wind of the spirit of investigation abroad and everywhere
there were magnificent results from it. This school of botany in
Germany with Valerius Cordus as the climax of it, whose untimely death
before thirty was indeed an irremediable loss to science, illustrates
this very well.
While the most important contributions to the science of botany during
that period came from the Germans, Italy did not lag far behind in
this subject, and France, Spain and Portugal supplied their quota to
the science. Above all, it is to the Italians that we owe editions of
Theophrastus, Dioscorides and the elder Pliny, works which contained
so much of information with regard to the science of botany in ancient
times and the modern publication of which brought about a reawakening
of interest in that subject corresponding to what was noted in
connection with every other republication of classical thought in the
various departments of the intellectual life. The most important of
the botanists of Italy was Caesalpinus, professor of botany at Padua
and director of the botanic garden there at the close of the Columbus'
Century, but who was afterwards physician to Pope Clement VIII. To
him, as we have seen in discussing the physiology of the time, we owe
a complete description of the circulation of the blood in the century
before Harvey. Caesalpinus is called by Linnaeus _primus verus
systematicus,_ the first true systematic botanist. His work, _"De
Plantis,"_ contains an immense amount of information and a complete
classification of all the then known plants, some 1520 in number, into
fifteen classes. The distinguishing characters of this classification
are taken from the fruit and show careful observation and thoroughly
scientific attention to details.
Caesalpinus' place in the history of botany can be best appreciated
from the praise of his colleagues in this department of science. John
Ray, the English botanist of the end of the seventeenth century, in
his history of plants declared that {379} Caesalpinus' book "On
Plants" was indeed a work from which much might be learned. Fabrucci
and Carl Fuchs declare Caesalpinus' treatise to be of first rank.
Thomas Garzon, Pona of Verona and Balthazar and Michael Campi in the
eighteenth century praised his work as thoroughly scientific. We have
already quoted Linnaeus' opinion of him and the modern father of
botany gladly accepted the suggestion of Plumier that a newly
discovered plant should be given the name of Caesalpinus, in order
that that name might be forever memorable in botany. Boerhaave, whom
we think of much more as a physician than a botanist, but some of
whose greatest work was done with regard to medical botany in the
University garden of Leyden, advised a friend and disciple if he could
buy any of Caesalpinus' works, to do so, for they were among the best
on the subject.
In France Ruellius, whose life is about equally divided between the
fifteenth and sixteenth centuries, was the physician to Francis I and
a distinguished botanist. He wrote scientific descriptions of a large
number of plants and put beside them the ordinary names which they
were called in various countries as he had obtained them from
peasants, farmers and country-people generally in his travels. His
work was an important contribution to the science of botany. Toward
the end of his life Ruellius, like his distinguished contemporary and
colleague, Linacre in England, became a priest. Another important
French contributor to the science is Pierre Belon of the first half of
the sixteenth century, though he had an interest in many other
biological sciences. He wrote a valuable treatise on coniferous plants
and a monograph on birds. This has attracted particular attention,
because in it "he compared the skeletons of birds and man in the same
posture and nearly as possible, bone for bone." As Garrison in his
"History of Medicine" (New York, 1913) says: "this was the first of
these serial arrangements of homologies which Owen and Haeckel made
famous." Belon travelled in Greece, Egypt and the Orient as well as
widely in Europe, mainly in the interests of _materia medica,_ but
everywhere picking up scientific information.
In Spain and Portugal writers in botany are the medical {380}
scientists and especially those who searched the Indies, West and
East, for plants with medicinal virtues. They did much both for pure
science and for medicine and some account of their work will be found
in the chapter on "Medicine" and "America in Columbus' Century." As
accumulators of information the biological scientists of all the
countries of Europe during Columbus' Century probably contributed more
to their various departments than their colleagues of any other
corresponding period in the history of science, even our own. They
had, of course, the advantage of fields ripe for the harvest, but they
undoubtedly took full advantage of their opportunities. Of all of them
might be said what Oliver Wendell Holmes said of the anatomists of the
Renaissance. They gathered in the rich harvest of discovery like the
harvesters in a grain field. After them in the next century came the
gleaners, who found many scattered precious grains of knowledge that
their predecessors with their rich harvest to care for had neglected.
Finally, in the later time, came into the field the geese, who found
here and there a grain of knowledge missed even by the gleaners and
who made a great cackling whenever they found one. The kindly satirist
was himself an anatomist, and we may take the exaggeration of his
picture with proper discount, yet with a recognition that it has much
more of truth than we always like to confess even to ourselves.
{381}