History of biology
(in old age), from the picture by Hagen-Schwarz.
(By permission of the Berlin Photographic Company, 133 New Bond Street,London, W.)
L. C. MIALL, D.Sc., F.R.S.,
FORMERLY PROFESSOR OF BIOLOGY IN THE UNIVERSITY OF LEEDS
[ISSUED FOR THE RATIONALIST PRESS ASSOCIATION, LIMITED]
WATTS & CO.,
17 JOHNSON'S COURT, FLEET STREET, E.C.
Biology of the ancients. Extinction of scientificinquiry. Revival of knowledge.
|PERIOD I (1530-1660)||7|
Characteristics of the period. The revival ofbotany. The revival of zoology. Early notions ofsystem. The first English naturalists. The rise ofexperimental physiology. The natural history ofdistant lands (sixteenth century and earlier). Agriculture,horticulture, and silk-culture in the sixteenthcentury.
|PERIOD II (1661-1740)||28|
Characteristics of the period. The minute anatomists.Early notions about the nature of fossils. Comparativeanatomy; the study of biological types. Adaptationsof plants and animals; natural theology.Spontaneous generation. The natural history ofJohn Ray. The scale of nature. The sexes offlowering plants.
|PERIOD III (1741-1789)||49|
Characteristics of the period. Systems of floweringplants; Linnæus and the Jussieus. Réaumur andthe History of Insects. The budding-out of newanimals (Hydra); another form of propagation withoutmating (aphids). The historical or comparativemethod; Montesquieu and Buffon. Amateur studentsof living animals. Intelligence and instinct in thelower animals. The food of green plants. Themetamorphoses of plants. Early notions about thelower plants.
|PERIOD IV (1790-1858)||89|
Characteristics of the period. Sprengel and thefertilisation of flowers. Cuvier and the rise ofpalæontology. Chamisso on the alternation ofgenerations in Salpa. Baer and the development ofanimals. The cell-theory. The scientific investigationof the higher cryptogams. The enrichment ofEnglish gardens. Humboldt as a traveller and abiologist. Premonitions of a biological theory ofevolution.
|PERIOD V (1859 and Later)||124|
Darwin on the Origin of Species. Pasteur's experimentalstudy of microbes.
|The Sub-Divisions of Biology||146|
LIST OF ILLUSTRATIONS
|Karl Ernst von Baer||Frontispiece|
|Figure From Fuchs' "Historia Stirpium"||8|
|Comparative Figures of Skeletons of Man and Bird, from Belon'sBook of Birds||14, 15|
|Antony van Leeuwenhoek||33|
|Georges Louis Leclerc, Comte de Buffon||65|
Four hundred years ago, say in the year 1500, Biology,the science of life, was represented chiefly by a slightand inaccurate natural history of plants and animals.Botany attracted more students than any other branch,because it was recognised as a necessary aid to medicalpractice. The zoology of the time, extracted fromancient books, was most valued as a source fromwhich preachers and moralists might draw impressiveemblems. Anatomy and physiology were taught out ofGalen to the more learned of physicians and surgeons.Some meagre notices of the plants and animals offoreign countries, mingled with many childish fables,eked out the scanty treatises of European naturalhistory. It was not yet generally admitted that fossilbones, teeth, and shells were the remains of extinctanimals.
It is the purpose of the following chapters to showhow this insignificant body of information expandedinto the biology of the twentieth century; how itbecame enriched by a multitude of new facts, strengthenedby new methods and animated by new ideas.
The Biology of the Ancients.
Long before the year 1500 there had been a short-livedscience of biology, and it is necessary to explainhow it arose and how it became quenched. Ancientbooks and the languages in which they are writtenteach us that in very remote times men attended to the2uses of plants and the habits of animals, gave names tofamiliar species, and recognised that while human lifehas much in common with the life of animals, it hassomething in common with the life of plants. Abundanttraces of an interest in living things are to be found inthe oldest records of India, Palestine, and Egypt. Stillmore interesting, at least to the inhabitants of WesternEurope, is the biology of the ancient Greeks. TheGreeks were an open-air people, dwelling in a singularlyvaried country nowhere far removed from the mountainsor the sea. Intellectually they were distinguishedby curiosity, imagination, and a strong taste forreasoning. Hence it is not to be wondered at thatnatural knowledge should have been widely diffusedamong them, nor that some of them should haveexcelled in science. Besides all the rest, the Greekswere a literary people, who have left behind them acopious record of their thoughts and experience. Greekscience, and Greek biology in particular, are thereforeof peculiar interest and value.
Greek naturalists in or before the age of Alexanderthe Great had collected and methodised the lore ofthe farmer, gardener, hunter, fisherman, herb-gatherer,and physician; the extant writings of Aristotle andTheophrastus give us some notion of what had beendiscovered down to that time.
Aristotle shows a wide knowledge of animals. Hedwells upon peculiar instincts, such as the migration ofbirds, the nest-building of the fish Phycis, the capture ofprey by the fish Lophius, the protective discharge ofink by Sepia, and the economy of the hive-bee. He isfond of combining many particular facts into generalstatements like these: No animal which has wings iswithout legs; animals with paired horns have cloven3feet and a complex, ruminating stomach, and lack theupper incisor teeth; hollow horns, supported by bonyhorn-cores, are not shed, but solid horns are shed everyyear; birds which are armed with spurs are neverarmed with lacerating claws; insects which bear a stingin the head are always two-winged, but insects whichbear their sting behind are four-winged. He tracesanalogies between things which are superficially unlike,such as plants and animals—the mouth of the animaland the root of the plant. The systematic naturalist isprone to attend chiefly to the differences betweenspecies; Aristotle is equally interested in their resemblances.The systematic naturalist arranges hisdescriptions under species, Aristotle under organs orfunctions; he is the first of the comparative anatomists.His conception of biology (the word but not the thingis modern) embraces both animals and plants, anatomy,physiology, and system. That he possessed azoological system whose primary divisions were nearlyas good as those of Linnæus is clear from the namesand distinctions which he employs; but no formalsystem is set forth in his extant writings. His treatiseon plants has unfortunately been lost.
Aristotle, like all the Greeks, was unpractised inexperiment. It had not yet been discovered that anexperiment may quickly and certainly decide questionswhich might be argued at great length without result,nor that an experiment devised to answer one questionmay suggest others possibly more important than thefirst. Deliberate scientific experiments are so rareamong the Greeks that we can hardly point to morethan two—those on refraction of light, commonlyattributed to Ptolemy, and those by which Pythagorasis supposed to have ascertained the numerical relations4of the musical scale. Aristotle was the last great manof science who lived and taught in Greece. Hiswritings disappeared from view for many centuries,and when they were recovered they were not so muchexamined and corrected as idolised.
Greece lost her liberty at Chaeronea, and with libertyher fairest hopes of continued intellectual development.Nevertheless, during a great part of a thousand yearsthe Greek and Semitic school of Alexandria cultivatedthe sciences with diligence and success. We must saynothing here about the geometry, astronomy, optics, orgeography there taught, but merely note that Herophilusand Erasistratus, unimpeded by that repugnanceto mutilation of the human body which had been insurmountableat Athens, made notable advances in anatomyand physiology. From this time a fair knowledge ofthe bodily structure of man, decidedly superior to thatwhich Aristotle had possessed, was at the command ofevery educated biologist.
The genius of Rome applied itself to purposes remotefrom science. The example of Alexandria had itsinfluence, however, upon some inhabitants of theRoman Empire. Galen of Pergamum in Asia Minorprosecuted the study of human anatomy. His knowledgeof the parts which can be investigated by simpledissection was extensive, but he was unpractised inexperimental physiology. Hence his teaching, thoughfull with respect to the skeleton, the chief viscera, andthe parts of the brain, was faulty with respect to theflow of the blood through the heart and body. Agesafter his death the immense reputation of Galen, likethat of Aristotle, was used with great effect to discreditmore searching inquiries. Under the Roman Empirealso flourished Dioscorides, who wrote on the plants used5in medicine, and the elder Pliny, who compiled a vast,but wholly uncritical, encyclopædia of natural history.
We see from these facts how ancient nations, inhabitingthe Mediterranean basin and largely guided byGreek intelligence, had not only striven to systematisethat knowledge of plants and animals which everyenergetic and observant race is sure to possess, buthad with still more determination laboured to create ascience of human anatomy which should be serviceableto the art of medicine. The effort was renewed timeafter time during five or six centuries, but was at lastcrushed under the conquests of a long succession offoreign powers—Macedonians, Romans, MohammedanArabs, and northern barbarians—each more hostile toknowledge than its predecessors.
Extinction of Scientific Inquiry.
The decline and fall of the Roman Empire broughtwith it the temporary extinction of civilisation in agreat part of Western Europe. Science was duringsome centuries taught, if taught at all, out of littlemanuals compiled from ancient authors. Geometry andastronomy were supplanted by astrology and magic;medicine was rarely practised except by Jews and theinmates of religious houses. Literature and the finearts died out almost everywhere.
No doubt the practical knowledge of the farmer andgardener, as well as the lore of the country-side, washanded down from father to son during all the ages ofdarkness, but the natural knowledge transmitted bybooks suffered almost complete decay. The teachingascribed to Physiologus is a sufficient proof of thisstatement. Physiologus is the name given in manylanguages during a thousand years to the reputed6author of popular treatises of zoology, which are alsocalled Bestiaries, or books of beasts. Here it was toldhow the lion sleeps with open eyes, how the crocodileweeps when it has eaten a man, how the elephant hasbut one joint in its leg and cannot lie down, how thepelican brings her young back to life by sprinklingthem with her own blood. The emblems of theBestiaries supplied ornaments to mediæval sermons;as late as Shakespeare's day poetry drew from them nosmall part of her imagery; they were carved on thebenches, stalls, porches, and gargoyles of the churches.
In the last years of the tenth century A.D. faint signsof revival appeared, which became distinct in anotherhundred years. From that day to our own the progresshas been continuous.
Revival of Knowledge.
By the thirteenth century the rate of progress hadbecome rapid. To this age are ascribed the introductionof the mariner's compass, gunpowder, readingglasses, the Arabic numerals, and decimal arithmetic.In the fourteenth century trade with the East revived;Central Asia and even the Far East were visited byEuropeans; universities were multiplied; the revivalof learning, painting, and sculpture was accomplishedin Italy. Engraving on wood or copper and printingfrom moveable types date from the fifteenth century.The last decade of this century is often regarded as theclose of the Middle Ages; it really marks, not thebeginning, but only an extraordinary acceleration, ofthe new progressive movement, which set in longbefore. To the years between 1490 and 1550 belongthe great geographical discoveries of the Spaniards inthe West and of the Portuguese in the East, as wellas the Reformation and the revival of science.
Characteristics of the Period.
This is the time of the revival of science; the revivalof