SCIENCE IN THE SEVENTEENTH CENTURY
The wonderful advances made in the mathematical, physical, and
astronomical sciences, and the invention of many new scientific
instruments, together with the publication of improved textbooks and
scientific tables, like those mentioned in the preceding chapter,
stimulated interest in other fields of science at the beginning of the
seventeenth century.
Medicine, which failed to advance with the astronomical and physical
sciences, began to improve. The Moors had established great medical
schools in Spain, but their teachings were based upon the principles
enunciated by Hippocrates and the Greek schools.
Modern medicine was started upon a firm basis by John Harvey
(1578-1657). Hippocrates taught that the blood was one of the principal
parts of the body--one of the four great "humors." Its movements,
however, had never been investigated until Harvey began to study the
functions of the arterial system by the dissection of animals. The
arteries had been considered as merely air tubes. This was due to the
fact that they were studied only in post-mortem examinations when they
were empty. The anatomists of the sixteenth century failed to grasp
their importance.
Harvey, who was a penetrating observer, had studied in several
continental universities as well as in England, and having an original
mind he determined to test the medical theories which he had been
taught. His discoveries of the functions of the heart, the arteries,
and the veins were epochal. He did his work so well and made such
simple, yet telling, demonstrations that he had less difficulty than
his predecessors in getting his teachings accepted. He was soon
recognized as the peer of Hippocrates and Galen.
Harvey died without actually seeing the blood coursing from the
arteries into the veins, but four years after his death Marcello
Malpighi (1628-1694) exhibited microscopically the passage of blood
corpuscles through the minute vessels in the lung of a turtle, on their
way from the heart through the arteries into the veins and returning to
the heart. The blood circulation was demonstrated at a subsequent date
by applying a microscope to the web of a frog's foot. With low-powered
lenses a good view is obtainable in this manner.
Many other important discoveries were made by Harvey, particularly
in embryology. He demonstrated that the embryo chicken is formed by
gradual development and processes of differentiation and not, as had
previously been believed, from a minute perfect chicken.
Microbes were discovered in 1683 by Antonius von Leeuwenhoek
(1632-1723), when he was examining some scrapings from his teeth. He
saw for the first time the long and short rods of bacilli and bacteria,
the spirillum and the micrococci. He tried means for destroying them
and met with a fair degree of success with a gargle composed of a
mixture of vinegar and hot coffee. This experiment was one of the early
anticipations of antiseptic surgery, which was invented by Lister in
the nineteenth century.
A French surgeon, Ambroise Paré (1517-1590) was a pioneer in the
treatment of wounds. The old method was to use boiling oil. He found
that by simply cleaning and bandaging wounds he could get better and
quicker results than with hot oil, which was a very painful treatment.
Paré used ligaments in stopping hemorrhages, improved the surgery in
harelip and hernia operations and for suprapubic lithotomy. He learned
the principles of these operations from Peter Franco (1505-1570), an
itinerant surgeon, who had much skill in operations for kidney and
bladder troubles.
Franz de la Boë (1614-1672), a professor in the university of Leyden,
who is best known under the name of Sylvius, the discoverer of the
brain fissure of Sylvius, founded a new school of chemical medicine.
Van Helmont suggested to him the possibility of the stomach being
the seat of many common disorders. When this was investigated, many
experiments were made with new medicines. The success of these
experiments led to a great reform in medical practice. Thomas Willis
(1622-1675), an English physician, completed the development of the
treatments suggested by Van Helmont and Sylvius as a result of their
studies of the works of Harvey.
Another great English medical genius arose to establish the practice
of medicine on a scientific basis. Thomas Sydenham (1624-1689) founded
a school of medicine in accordance with these three principles: (1)
Accurate descriptions of the courses of diseases, (2) following a
fixed method of treatment in each disease, (3) searching for specific
remedies for each diseased condition.
The results of these teachings were very pronounced. Before Sydenham's
time, the only drug used in medicine was an extract of cinchona. The
Dutchmen above named and Sydenham discovered many active medicinal
substances. Sydenham's principal discovery in materia medica was that
of the properties of laudanum.
William Gilbert, court physician to Queen Elizabeth of England,
while Galileo and Stevin were developing the laws of gravitation and
hydrodynamics, undertook the investigation of the laws of terrestrial
magnetism and chemistry. His researches in chemistry were extensive and
valuable. His fame, however, was perpetuated by his study of magnetism
and electricity. He found that the earth is a vast magnet with north
and south poles. His remarkable textbook on magnetism covered many of
the fundamental facts known to-day. He noted the distinction between
magnetism and electricity, described electrical charges, the principles
of conductivity and methods for magnetizing iron. Galileo wrote of him:
"I extremely admire and envy this author."
The mercurial barometer and its laws were discovered by Evangelista
Torricelli (1608-1647) a student of Galileo. By means of his barometer,
Torricelli was able to make great advances in knowledge relating to
the physics of the air and to gas pressures, and he investigated the
principles of hydraulics. The microscope, telescope, sextant and other
instruments were greatly improved by him, and his mathematical work
ranks only second to his contributions to experimental science.
The Torricellian tube, used as a barometer, was a means of creating a
vacuum, which was formed at the top of the column of mercury. Pascal,
the French mathematician, took up the study of the physics of the
vacuum and published an important work on his own experiments. These
and other experiments made by European scientists prepared the ground
for, and suggested, the investigations of gases and vacua by Boyle,
Mariotte, and others which finally resulted in the invention of the
steam engine and many other modern machines.
Robert Boyle (1627-1691) published at Oxford in 1660 a book which
distinguished between chemical compounds and chemical mixtures. He
adopted the use of the term gas, which was first proposed by Van
Helmont, and made some valuable studies on the physics of boiling and
freezing. The oxidation of metals, the results of calcination, and
of the fusing of metals and alloys, calculation of the atmospheric
pressure, a study of colors as affected by light rays, and
investigations in electricity were among the scientific works carried
out by this great experimenter. But his fame rests mainly upon the
results of his researches on gases.
Boyle began life as an alchemist and died a well-trained chemist.
Edme Mariotte, a French contemporary of Boyle's, carried out similar
experiments and assisted in formulating the physical laws of gases
bearing the names of Boyle and Mariotte.
A German physicist, Otto von Guericke (1602-1686), also followed up
Boyle's work and invented a new form of air pump. He also carried on
important experiments in electricity.
Gilbert, Harvey, Van Helmont, Torricelli, Boyle, Mariotte, and other
similar pioneers in scientific methods not only invented numerous
valuable instruments and wrote suggestive textbooks, but advanced
scientific learning and the love of it by their delightful accounts of
their experiments.
Modern education started with these men. Before this period there
had been a sterile age in which the fundamental purpose of education
was only to teach men how to protect the soul and to serve God.
This humanistic principle, however, failed to advance knowledge of
the laws of nature, and the researches of the scientists gradually
caused a strong reaction against it. This in turn resulted in further
advances being made, not only in the sciences, but in all departments
of learning. The way was paved for the era of naturalism, developed
by Hobbes, Locke, Descartes, Voltaire, Kant, Rousseau, and others.
Naturalism aimed at explaining all phenomena in the simplest terms, and
correlating all things by universal principles. It has received a great
impetus in modern times from the Darwinian theory of evolution.
The great scientific discoveries of the sixteenth and seventeenth
centuries had other important educational effects. They led
to professional specialization and the founding of scientific
institutions, schools, and universities. The Lyncean Society of
Scientists was founded in Italy in Galileo's time. It subsequently
became, in 1657, the Accademia del Cimento.
The Royal Society of England was organized about 1645 and chartered in
1662. It did much valuable scientific work from its inception. It has
assisted the foremost scientists in their work, directed scientific
researches, and financed the printing of scientific records and the
carrying out of foreign expeditions. Nearly all the leading countries
in the world have formed institutions with similar aims.
The chemical discoveries of Boyle attracted widespread attention
and led to investigations started with the view of discovering the
constitution of matter. Hermann Boerhaave (1668-1738) of Leyden, took
up the study of organic chemistry. Stephen Hales (1677-1761) did
similar work in England. Both of these chemists invented valuable
laboratory processes and instruments. Hales improved the pneumatic
trough used for collecting gases.
Scientists were now furnished with the telescope, compass, sextant,
microscope, barometer, thermometer, air pump, manometer, and other
instruments so that cellular structures of plants, animals, and
insects, the microbes and bacteria, the animalculæ found in water and
in the sea, as well as the phenomena of the air, sky, and earth crust
could now be studied by trained observers. The invention of these
instruments caused workers to specialize more and more, and completely
severed science from philosophy, of which it had been an appendage
since the earliest times.
The microscopical investigations of Malpighi, Kircher, Leeuwenhoek,
Grew, and Hooke opened up an immense field for research. They developed
microscopical chemistry and anatomy, and changed the prevailing ideas
regarding animal and vegetable tissues. The sciences of mineralogy,
botany and entomology were benefited and the medical sciences were
practically revolutionized. The first publications of the Royal Society
show the widespread attention microscopical and telescopic studies were
then receiving.
[Illustration:
Copyright, Keystone View Co.
WEATHER AND ASTRONOMICAL INSTRUMENTS ON THE ROOF OF GREENWICH
OBSERVATORY, ENGLAND]
[Illustration:
Courtesy "Aeronautics," London
A MOORING TOWER FOR AIRSHIPS, WITH THE R-24 FASTENED HEAD ON]
Francis Bacon (1561-1626), René Descartes (1596-1650) and Gottfried
Leibnitz (1646-1716), in England, France, and Germany, respectively,
lent powerful aid to the advance of science at this time.
Bacon's great learning enabled him effectively to describe scientific
methods and to direct scientific criticism. He attracted general
attention to scientific methods based on inductive processes.
Descartes, seeing that the world's best intellects had long been
exercised with philosophy and metaphysics, without discovering anything
with certainty, resolved to accept no beliefs upon the authority of
any name or reputation. He would reach his own conclusions based upon
the scrupulous examination of data. He hoped to solve the mysteries
of nature by the aid of mathematics and geometry, and developed the
Cartesian philosophy.
The mathematical works of Descartes are now better known than his
general scientific ideas. He published in 1637 his "Discourses on
Method" and on Geometry. In the last-named work, suggestions are given
for the development of analytic methods. It has been said of his
formulæ that they are even cleverer than himself. The general use of
his analytic methods by other mathematicians resulted in the solution
of many scientific problems that had been handed down for centuries as
insoluble.
Descartes also advanced algebra. The application of the doctrine of
curved lines to algebra greatly enlarged the scope of its usefulness.
In making these innovations, Descartes introduced the methods and
symbols of modern exponential notation. The English mathematician
Wallis was also an important agent in the development of mathematical
notation. He based his work on the Greek notation and that of Nicolas
Chuquet (1484), J. Bürgi, Thomas Harriot (1631), Johann Hudde (1659),
and others. Descartes was familiar with the writings of these scholars
and, undoubtedly, was influenced by them.
Roberval, Fermat, and Pascal were contemporary mathematicians in France
and left great names in the history of the mathematical sciences. They
all made contributions which permanently enriched mathematics and made
further progress in other sciences possible.
The geographical sciences now began to attract attention. The new
scientific instruments made it possible to collect data in all parts of
the world that was needed in unraveling scientific mysteries.
William Dampier (1653-1715) was one of the pioneers in scientific
voyages of discovery. In voyages to the Orient and Australasia he
collected much important data on zoölogy, botany, meteorology, the
winds, tides, currents, and on fish and sea life. His book on winds
became the first great standard work on meteorology.
The doctrine of spontaneous generation had long held sway in Europe.
The Greeks entertained it and it was accepted as true in the time of
Martin Luther. Francesco Redi (1626-1697), an Italian biologist, showed
that when the flesh of dead animals is protected it remains fresh.
The Abbé Spallanzani (1729-1799) carried Redi's theory further and
showed that microbes and bacteria do not develop in concoctions which
have been boiled and sealed. Here we note the beginning of antiseptic
science.
Under the leadership of Bacon in England, Calvin in France, Luther
in Germany, and Knox in Scotland, European thought was being stirred
up while the great discoveries just related were being made. Just
as Boyle's chemical discoveries caused the divorcing of chemistry
from alchemy, and the naturalistic philosophy of the times led to
the specialization of scientists and the breaking off of philosophy
from science, so the intellectual awakening aroused by Bacon and his
contemporaries led to the suppression of belief in witchcraft and to
revolutionary ideas in religion and ethics.
Locke endeavored to base a "rational Christianity" on the ground of
experience. Until his times, theology was tangled up with a maze of
physical problems which dismayed even such intellects as those of
Newton, Hume, and Locke.
Newton's researches were chiefly based upon mathematical and
astronomical problems. While a student at Cambridge in 1660, he studied
the works of Descartes, Kepler, Van Schooten, Barrow, and particularly
those of the Greek and British mathematicians. The works of J. Wallis
were very valuable to him. The "Arithmetic of Affinities" of Wallis
drew his attention to astronomical problems and thus led to his great
triumphs later on.
Newton's "Principia" has already been referred to as being one of the
greatest works of the intellect ever produced.
The result of Newton's meditation upon the nature of the central
force that keeps the planets in their courses was that he furnished a
mathematical basis for Kepler's laws by proving that if the planets
describe elliptical orbits about the sun, the force acting toward the
sun, keeping them in revolution, must vary inversely as the square of
the distance. On the revolution of the moon around the earth he found a
practical confirmation of this law of gravitational attraction. He then
took up the study of motion in general and showed that every particle
of matter attracts every other particle in accordance with the same
principle of inverse squares.
Botanical gardens were established in Padua in 1545, and not long after
in Pisa, Leyden, Paris, and London. Much attention was devoted to
medicinal plants, and numerous herbal books were published. Malpighi,
Grew, and Camerarius (1665-1721) published works on botany and plant
morphology. Ray and Linnæus (1707-1778) studied the classification of
plants and compiled textbooks of descriptive botany.
Buffon (1707-1788) published his famous "Natural History of Animals"
which did for zoölogy what the works of Linnæus did for botany.
Looking backward, we can now see that all scientific knowledge has
been gained by the trial and error method and cumulative analyses of
a multitude of observations. Progress is not made uniformly but in a
recurrent, cyclic manner. Reactions follow advances, but in the end all
goes forward.