Read Ebook: Fathers of Biology by McRae Charles

Font size: 10 px 15 px 20 px 25 px 30 px 35 px

Background color: BlackWhiteGrayLight GrayDark GrayDim Gray

Text color: BlackWhiteGrayLight GrayDark GrayDim Gray

Apply/Save settings

Ebook has 265 lines and 25035 words, and 6 pages

The manuscripts of Aristotle's works passed through many vicissitudes. At the death of the philosopher they were bequeathed to Theophrastus, who continued chief of the Peripatetic school for thirty-five years. Theophrastus left them, with his own works, to a philosophical friend and pupil, Neleus, who conveyed them from Athens to his residence at Scepsis, in Asia Minor. About thirty or forty years after the death of Theophrastus, the kings of Pergamus, to whom the city of Scepsis belonged, began collecting books to form a library on the Alexandrian plan. This led the heirs of Neleus to conceal their literary treasures in a cellar, and there the manuscripts remained for nearly a century and a half, exposed to injury from damp and worms. At length they were sold to Apellicon, a resident at Athens, who was attached to the Peripatetic sect. Many of the manuscripts were imperfect, having become worm-eaten or illegible. These defects Apellicon attempted to remedy; but, being a lover of books rather than a philosopher, he performed the work somewhat unskilfully. When Athens was taken by Sylla, 86 B.C., the library of Apellicon was transported to Rome. There various literary Greeks obtained access to it; and, among others, Tyrannion, a grammarian and friend of Cicero, did good service in the work of correction. Andronicus of Rhodes afterwards arranged the whole into sections, and published the manuscripts with a tabulated list.

The three principal works on biology which are extant are: "The History of Animals;" "On the Parts of Animals;" "On the Generation of Animals." The other biological works are: "On the Motion of Animals;" "On Respiration;" "Parva Naturalia;"--a series of essays which are planned to form an entire work on sense and the sensible.

"The History of Animals" is the largest and most important of Aristotle's works on biology. It contains a vast amount of information, not very methodically arranged, and spoiled by the occurrence here and there of very gross errors. It consists of nine books.

The first book opens with a division of the body into similar and dissimilar parts. Besides thus differing in their parts, animals also differ in their mode of life, their actions and dispositions. Thus some are aquatic, others terrestrial; of the former, some breathe water, others air, and some neither. Of aquatic animals, some inhabit the sea, and others rivers, lakes, or marshes. Again, some animals are locomotive, and others are stationary. Some follow a leader, others act independently. Various differences are in this way pointed out, and there is no lack of illustration and detail, but a suspicion is excited that the generalizations are sometimes based upon insufficient facts. The book closes with a description of the different parts of the human body, both internal and external. In speaking of the ear, Aristotle seems to have been aware of what we now call the Eustachian tube, for he says, "There is no passage from the ear into the brain, but there is to the roof of the mouth."

In the second book he passes on to describe the organs of animals. The animals are dealt with in groups--viviparous and oviparous quadrupeds, fish, serpents, birds, etc. The ape, elephant, chameleon, and some others are especially noticed.

Books five to seven deal with the subject of generation.

The eighth book contains a variety of details respecting animals, their food, migrations, hibernation, and diseases; with the influence of climate and locality upon them.

In the work "On the Parts of Animals," the author considers not only the phenomena of life exhibited by each species, but also the cause or causes to which these phenomena are attributable. After a general introduction, he proceeds to enumerate the three degrees of composition, viz.:--

"Composition out of what some call the elements, such as air, earth, water, and fire," or "out of the elementary forces, hot and cold, solid and fluid, which form the material of all compound substances."

Composition out of these primary substances of the homogeneous parts of animals, e.g. blood, fat, marrow, brain, flesh, and bone.

Composition into the heterogeneous parts or organs. These parts he describes in detail, considering those belonging to sanguineous animals first and most fully.

These divisions correspond roughly to the threefold study of structure which we nowadays recognize as chemical, histological, and anatomical.

As examples of Aristotle's method of treatment, his descriptions of blood, the brain, the heart, and the lung may be considered.

From these quotations it will be noted that Aristotle attributed the coagulum to the presence of fibres, and in this he anticipated Malpighi's discovery made in the seventeenth century. His remarks on the proportion of coagulum and serum in different animals, which is enlarged upon in the "History of Animals," harmonize with modern observations. In another of his works he remarks that the blood in certain diseased conditions will not coagulate. This is known to be the case in cholera, certain fevers, asphyxia, etc.; and the fact was probably obtained from Hippocrates. Although Aristotle speaks here of entire absence of coagulation in the blood of the deer and the roe, in the "History of Animals" he admits an imperfect coagulation, for he says, "so that their blood does not coagulate like that of other animals." The animals named are commonly hunted, and it was probably after they had been hunted to death that he examined them. Now, it is generally admitted that coagulation under such circumstances is imperfect and even uncommon. The statement as to the richness in fibres of the blood of bulls and boars has been confirmed by some modern investigations, which have shown that the clot bears a proportion to the strength and ferocity of the animal. The remarks, however, as to the relative rapidity of coagulation would appear to be contradicted by later observations, for Thackrah came to the conclusion that coagulation commenced sooner in small and weak animals than in strong.

The treatise "On the Generation of Animals" is an extraordinary production. "No ancient and few modern works equal it in comprehensiveness of detail and profound speculative insight. We here find some of the obscurest problems of biology treated with a mastery which, when we consider the condition of science at that day, is truly astounding. That there are many errors, many deficiencies, and not a little carelessness in the admission of facts, may be readily imagined; nevertheless at times the work is frequently on a level with, and occasionally even rises above, the speculations of many advanced embryologists."

In later times the two great rival theories put forward to account for the development of the embryo have been--

The theory of Evolution, which makes the embryo pre-existent in the germ, and only rendered visible by the unfolding and expansion of its organs.

The theory of Epigenesis, which makes the embryo arise, by a series of successive differentiations, from a simple homogeneous mass into a complex heterogeneous organism.

The above quotation will show how closely Aristotle held to the theory of Epigenesis; and in another place he says, "Not at once is the animal a man or a horse, for the end is last attained; and the specific form is the end of each development."

A chapter of this work is devoted to the consideration of the hereditary transmission of peculiarities from parent to offspring.

The fifth and last book contains inquiries into the cause of variation in the colour of the eyes and hair, the abundance of hair, the sleep of the embryo, sight and hearing, voice and the teeth.

Widely different opinions have been held from time to time of the value of Aristotle's biological labours. This philosopher's reputation has, perhaps, suffered most from those who have praised him most. The praise has often been of such an exaggerated character as to have become unmeaning, and to have carried with it the impression of insincerity on the part of the writer. Such are the laudations of Cuvier. To say as he does, "Alone, in fact, without predecessors, without having borrowed anything from the centuries which had gone before, since they had produced nothing enduring, the disciple of Plato discovered and demonstrated more truths and executed more scientific labours in a life of sixty-two years than twenty centuries after him were able to do," is of course to talk nonsense, for the method which Aristotle applied was that which Hippocrates had used so well before him; and it is evident to any one that both his predecessors and contemporaries are frequently laid under contribution by Aristotle, although the authority is rarely, if ever, stated by him unless he is about to refute the view put forward. Exaggerated praise of any author has a tendency to excite depreciation correspondingly unjust and untrue. It has been so in the case of this great man. In the endeavour to depose him from the impossible position to which his panegyrists had exalted him, his detractors have gone to any length. The principal charges brought against his biological work have been inaccuracy and hasty generalization. In support of the charge of inaccuracy, some of the extraordinary statements which are met with in his works are adduced. "These," Professor Huxley says, "are not so much to be called errors as stupidities." Some, however, of the inaccuracies alleged against Aristotle are fancied rather than real. Thus he is charged with having represented that the arteries contained nothing but air; that the aorta arose from the right ventricle; that the heart did not beat in any other animal but man; that reptiles had no blood, etc.; although in reality he made no one of these assertions. There remain, nevertheless, the gross misstatements referred to above, and which really do occur. Such, for instance, as that there is but a single bone in the neck of the lion; that there are more teeth in male than in female animals; that the mouth of the dolphin is placed on the under surface of the body; that the back of the skull is empty, etc. Although these absurdities undoubtedly occur in Aristotle's works, it by no means follows that he is responsible for them. Bearing in mind the curious history of the manuscripts of his treatises, we shall find it far more reasonable to conclude that such errors crept in during the process of correction and restoration, by men apparently ignorant of biology, than that an observer who had distinguished the cetacea from fishes and had detected their hidden mammae, discovered their lungs, and recognized the distinct character of their bones, should have been so blind as to fancy that the mouth of these animals was on the under surface of the body.

That Aristotle made hasty generalizations is true; but it was unavoidable. Biology was in so early a stage that a theory had often of necessity to be founded on a very slight basis of facts. Yet, notwithstanding this drawback, so great was the sagacity of this philosopher, that many of his generalizations, which he himself probably looked upon as temporary, have held their ground for twenty centuries, or, having been lost sight of, have been discovered and put forward as original by modern biologists. Thus "the advantage of physiological division of labour was first set forth," says Milne-Edwards, "by myself in 1827;" and yet Aristotle had said that "whenever Nature is able to provide two separate instruments for two separate uses, without the one hampering the other, she does so, instead of acting like a coppersmith, who for cheapness makes a spit-and-a-candlestick in one. It is only when this is impossible that she uses one organ for several functions."

In conclusion, we may say that the great Stagirite expounded the true principles of science, and that when he failed his failure was caused by lack of materials. His desire for completeness, perhaps, tempted him at times to fill in gaps with such makeshifts as came to his hand; but no one knew better than he did that "theories must be abandoned unless their teachings tally with the indisputable results of observation."

FOOTNOTES:

Pliny, "Natural History," viii. c. 16.

"History of Animals," i. 11.

Bk. iii. 19.

"Meteorology," iv. 7-11.

"History of Animals," i. 16.

"History of Animals," vi. 3.

"On some of the errors attributed to Aristotle."

"History of Animals," i. 17.

See Professor Huxley's article already referred to.

"Aristotle," by G. H. Lewes, p. 325.

"De Part. Anim.," iv. 6.

???????????????.

"De Gener.," iii. 10, quoted by Dr. Ogle.

GALEN.

Under the Ptolemies a powerful stimulus was given to biological studies at Alexandria. Scientific knowledge was carried a step or two beyond the limit reached by Aristotle. Thus Erasistratus and Herophilus thoroughly investigated the structure and functions of the valves of the heart, and were the first to recognize the nerves as organs of sensation. But, unfortunately, no complete record of the interesting work carried on by these men has come down to our times. The first writer after Aristotle whose works arrest attention is Caius Plinius Secundus, whose so-called "Natural History," in thirty-seven volumes, remains to the present day as a monument of industrious compilation. But, as a biologist properly so called, Pliny is absolutely without rank, for he lacked that practical acquaintance with the subject which alone could enable him to speak with authority. Of information he had an almost inexhaustible store; of actual knowledge, the result of observation and experience, so far as biological studies were concerned, he had but little. This was largely due to the encyclopaedic character of the work he undertook; his mental powers were weighed down by an enormous mass of unarranged and ill-digested materials. But it was due also to the peculiar bent of Pliny's mind. He was not, like Aristotle, an original thinker; he was essentially a student of books, an immensely industrious but not always judicious compiler. Often his selections from other works prove that he failed to appreciate the relative importance of the different subjects to which he made reference. His knowledge of the Greek language appears, too, to have been defective, for he gives at times the wrong Latin names to objects described by his Greek authorities. To these defects must be added his marvellous readiness to believe any statement, provided only that it was uncommon; while, on the other hand, he showed an indefensible scepticism in regard to what was really deserving of attention. The chief value of his work consists in the historical and chronological notes of the progress of some of the subjects of which he treats--fragments of writings which would otherwise be lost to us. Pliny was killed in the destruction of Pompeii, A.D. 79.

Claudius Galenus was born at Pergamus, in Asia Minor, in the hundred and thirty-first year of the Christian era. Few writers ever exercised for so long a time such an undisputed sway over the opinions of mankind as did this wonderful man. His authority was estimated at a much higher rate than that of all the biological writers combined who flourished during a period of more than twelve centuries, and it was often considered a sufficient argument against a hypothesis, or even an alleged matter of fact, that it was contrary to Galen.

With the Emperor M. Aurelius he returned to Rome, and became afterwards doctor to the young Emperor Commodus. He did not, however, remain for a long period at Rome, and probably passed the greater part of the rest of his life in his native country.

Although the date of his death is not positively known, yet it appears from a passage in his writings that he was living in the reign of Septimius Severus; and Suidas seems to have reason for asserting that he reached his seventieth year.

Galen's writings represent the common depository of the anatomical knowledge of the day; what he had learnt from many teachers, rather than the results of his own personal research. Roughly speaking, they deal with the following subjects: Anatomy and Physiology, Dietetics and Hygiene, Pathology, Diagnosis and Semeiology, Pharmacy and Materia Medica, Therapeutics.

He supposed that there were three modes of existence in man, namely--

The nutritive, which was common to all animals and plants, of which the liver was the source.

The vital, of which the heart was the source.

The rational, of which the brain was the source.

Again, he considered that the animal economy possessed four natural powers--

The attractive.

The alterative or assimilative.

Share on: WhatsApp @Hash Facebook Tweet