Part 13

The female then only provides the material, the male the soul, the form, the principle, that which makes life. Aristotle was thus prepared to accept instances of fertilization without material contact, i.e., in effect, parthenogenesis or ‘virgin birth’. In the centuries that came after him such instances were not infrequently adduced, and this doctrine was given a special turn by Christian theologians. Belief in the ‘accidental’ character of the material contribution of the male was common among men of science till the nineteenth century. The general attitude as to the nature of fertilization set forth, for instance, by William Harvey (1578-1657, pp. 111-14) in his book, On the Generation of Animals, published in London in A.D. 1651, is practically identical with the views of Aristotle published in Athens about 350 B.C., just 2,000 years earlier. It is of great interest to note that very recent embryological research goes some way to confirm this view of Aristotle. Without any intervention of the male sexual element, it is possible so to stimulate the egg mechanically as to produce a perfect animal which is thus fatherless from the first. The male element is indeed unnecessary and, in fact, transmits only hereditary characters.

We must say something concerning Aristotle’s conceptions of the nature of Life itself. He was before all things a ‘vitalist’. For him the distinction between living and not-living substance is to be sought not in material constitution, but in the presence or absence of something that he calls psyche, which we may translate ‘Soul’. His teaching on this topic had the profoundest influence on subsequent anatomical and physiological thought.

Aristotle’s theory as to the relation of this Soul to material things is a difficult and complicated subject. Its adequate discussion would take us beyond our theme. He holds, however, that the Soul is related to the idea of form. In living things the soul is that which gives form. It is the pervasion by the soul that leads to the determinate development of the body and its parts. This activity of the Soul, under the Aristotelian term Entelechy (which we may perhaps translate ‘the indwelling perfectability’ or ‘purposiveness’, see Preface), has an important place in modern biological theory, which has, indeed, swung definitely in the direction of the Aristotelian position.

Aristotle defines Life, existing in Matter, as ‘the power of self-nourishment and of independent growth and decay’. Of the Soul, the principle of Life, he distinguishes three orders or types, the lowest vegetative, or nutritive and reproductive, next the animal or sensitive, and highest the rational or intellectual soul. The last, he at first held, was peculiar to man, but later he modified this view.

The history of the reception of Aristotle’s science by later ages is very strange to modern eyes. Of all Aristotle’s scientific teachings, men clung most firmly for many centuries not to his finely thought-out biological conceptions, but to a doctrine of the constitution of matter of which the modern student hears nothing. Aristotle, following more ancient writers, held that there were four primary and opposite fundamental Qualities, the hot and the cold, the wet and the dry. These met in binary combination to constitute the four Essences or Existences which entered in varying proportions into the constitution of all Matter. The four Essences, or, to give them their usual name, Elements, were earth, air, fire, and water. Thus, water was wet and cold, fire hot and dry, and so forth. With this theory later writers combined the somewhat similar Hippocratic doctrine which held that the body was composed of the four ‘Humors’ or liquids: blood, phlegm, black bile (melancholy), and yellow bile (choler). Some of the Hippocratic physicians had associated excess of the Humors with various types of bodily constitution. Their followers made much of the ‘temperaments’ resulting therefrom, and according to the prevailing humor they distinguished the sanguine, phlegmatic, melancholy or choleric temperament (Fig. 34, p. 97).

These conceptions, now departed altogether from our scientific discipline, still persist embedded in our language. Poetry still uses such ideas as the ‘raging of the elements’ and ‘elemental forces’. We may yet speak of a ‘fiery nature’ or an ‘aerial spirit’. We know what is meant by a sanguine or a phlegmatic temperament, and a melancholy or choleric disposition, and such words conjure up real pictures in our minds (Fig. 34). Until it began to be undermined by Robert Boyle (1627-91) and others in the seventeenth century, the doctrine of the four elements persisted in its entirety, while ideas and terms derived from the old humoral pathology can, in fact, be traced in the medicine of the twentieth century.

The biological activity of the school of Aristotle was continued after his death by his pupil Theophrastus (372-287 B.C.). Especially the writings on plants of Theophrastus are instinct with a thoroughly scientific spirit, and are rightly regarded as the basic documents of the science of Botany. Nevertheless, his works had little effect or influence on his contemporaries and successors. With Theophrastus the purely biological school of Aristotle may be said to come to an end. The biological sciences ceased, for many centuries, to be studied for their own sake and became mere handmaidens of Medicine. Neither mistress nor servant was the better for the change.

THE HEIRS OF GREECE

(300 B.C. TO A.D. 200.)

§ 1. The Alexandrian School.

Soon after Aristotle, about 300 B.C., a great medical school was founded at Alexandria in Egypt. That country had been conquered by Alexander the Great, after whom the town was named. On Alexander’s death, Egypt came under the rule of one of his generals, Ptolemy, who established a dynasty which became extinct with the famous Queen Cleopatra, thirty years before the Christian era. Alexandria was a favorite residence of this Greek dynasty and became more Greek than Egyptian. Ptolemy and his successors were patrons of learning, and at the Alexandrian school remarkable anatomical and physiological researches were made. These were the work of Greek physicians who, in the tradition of their people, were only too wont to associate their discoveries with sweeping theoretical generalizations, often on very inadequate bases.

The two earliest medical teachers at Alexandria were also the greatest, Herophilus of Chalcedon, who flourished about 300 B.C., and his slightly younger contemporary Erasistratus of Chios. Herophilus may be regarded as the father of Anatomy, Erasistratus as the father of Physiology.

Herophilus was probably the first to dissect the human body in public. He recognized the brain as the central organ of the nervous system and regarded it as the seat of the intelligence, thus reversing the verdict of Aristotle on the primacy of the heart. He was the first to grasp the nature of the nerves, which he distinguished as connected with motion and sensation (Fig. 98), though he did not separate them clearly from tendons and sinews. He greatly extended the knowledge of the parts of the brain. Certain parts of the brain still bear titles which are translations of those which he gave them. He also made the first clear distinction between arteries and veins.

At the time of the institution of the Alexandrian medical school, and for long after, there flourished that view of the structure of the world known as atomic, propounded by the philosopher Democritus (c. 400 B.C.). The chief exponent of the theory was Epicurus (342-270), whose philosophy was of the order which we should now call ‘materialistic’. For it the only ultimate realities were atoms and ‘the void’, and everything was ultimately expressible in these terms. Epicurean philosophy was not without its reactions on Medicine at Alexandria, where its leading exponent was Erasistratus of Chios.

Erasistratus was essentially a rationalist and professed himself a foe to all mysticism. In the last resort, however, he had to invoke the idea of Nature as a great artist acting as an external power, shaping the body according to the ends to which it must act. This is in contrast with Aristotle’s view of the ‘soul’ as an Entelechy (p. 33), an innate and inherent factor. Erasistratus sought to express his views in atomic terms, but, to make physiology intelligible, he added a conception, Pneumatism, found also among older thinkers. Pneumatism is the belief that the phenomena of life are associated with the existence of a subtle vapor, ‘pneuma’ or spirit, which permeates the organism, and causes its movements. This subtle vapor is held to have some affinities with the air we breathe. Pneumatism is, in fact, a primitive attempt to explain the phenomena of respiration.

Erasistratus observed that every organ is equipped with a threefold system of ‘vessels’, vein, artery, and nerve, which divide to the very limits of vision, and he considered that the process of division continues beyond those limits. The minute divisions of these vessels, plaited together, he believed to make up the tissues. Veins, arteries, and nerves are, for him, made of minute tubes of the same nature as themselves, through which they are nourished. Blood and two kinds of pneuma are the essential sources of nourishment and movement. The blood is carried by veins. Air, on the other hand, is taken in by the lungs and passes to the heart, where it becomes changed into a peculiar pneuma, the Vital Spirit, which is sent to the various parts of the body by the arteries. This spirit is carried to the brain, in the cavities or ‘ventricles’ of which it is further changed to a second kind of pneuma, the Animal Spirit. The animal spirit is conveyed to different parts of the body by the nerves, which are hollow.

In the brain Erasistratus observed the convolutions, noted that they were more elaborate in man than in animals, and associated this complexity with the higher intelligence of man. He distinguished between the main parts of the brain, the ‘cerebrum’ and ‘cerebellum’ (Fig. 100, p. 210), and gave a detailed description of the ‘cerebral ventricles’ or cavities within the brain and of the ‘meninges’ or membranes that cover the brain. He considered that the cerebral ventricles were filled with Animal Spirit. (Compare Galen’s scheme, p. 58.)

Erasistratus attained to a clear view of the action of muscles in producing movement. He regarded the shortening of muscles as due to distension by Animal Spirit conveyed to the muscles by the nerves. We may note that similar theories as to the nature of muscular action were again set forth, on theoretical grounds, in the seventeenth century by Descartes (1596-1650, pp. 127-8) and by Borelli (1608-79, pp. 129-30), but were rebutted by the experiments of Swammerdam (1637-80, p. 123). We may recall that we are still in the dark as to the mechanism of contraction of muscle fiber, the structure of which was first revealed by Leeuwenhoek (1632-1723, Figs. 55-56A, p. 121).

Erasistratus considered the chief cause of disease to be excess of blood or Plethora. Diseases thus caused differ according to their site. Among them are coughing of blood, epilepsy, pneumonia, tonsillitis, &c. Most of these diseases could be treated by diminishing the local supply of blood by starvation. Among his contemporaries and successors blood-letting was an habitual practice applied to almost every condition. Erasistratus employed it but rarely, and his followers banned it altogether. He was consistently opposed to violent remedies. Among the therapeutic measures which he favored were regulated exercise, diet, and the vapor bath.

Erasistratus complained that many physicians of his time were not interested in Hygiene. He therefore wrote a treatise on the subject. Though he regarded Hygiene as a means of substituting prevention for cure, this did not prevent him from being extremely careful and precise in his treatment of cases.

After the first generation or two, the activity of the Alexandrian medical school flagged, though the city long remained a great teaching center, and minor medical advances were made. Surgery (cf. Fig. 14) seems to have languished less than Medicine. The stagnation in medical matters at Alexandria is in contrast to the continued activity there in Mathematics, Astronomy, Mechanics and Geography.

With the absorption of Egypt into the Roman Empire in 50 B.C. and the extinction of the Ptolemaic dynasty by the death of Cleopatra in 30 B.C., Alexandria ceased to have great scientific importance. The school continued for centuries with restricted activity and devoid of all originality. Intellectually, it had become subordinate to the Metropolis. Rome was now mistress of the world and the future of Medicine must be considered from the point of view of the Roman Empire.

FIG. 14. INSCRIBED TABLET OF ABOUT 100 B.C. from the wall of the temple of Kom-Ombos in Upper Egypt. The temple itself was built by Ptolemy VII (181-146 B.C.), but the carving is later. It is divided into four partitions. These illustrate the surgical instruments in use in Egypt during Alexandrian times.

In the partition to the extreme left can be seen two cupping-glasses (cf. Fig. 8), a case of instruments (cf. Fig. 15), a pair of shears, a sponge, a probe, a pair of fine forceps, and two knives (cf. Fig. 9).

In the next partition to the right can be seen two large forceps, two bags or flasks, a strigil, two magic eyes, a pair of scales, and two growing plants.

In the next partition to the right can be seen several hooks of different forms, several knives, and two or three pairs of forceps.

In the partition to the extreme right can be seen a bifid probe, a pair of tongs, a long-bladed knife, probes, a double hook, a saw, a cautery, and several objects probably intended to represent bandages. ]

§ 2. Medical Teaching in the Roman Empire.