Altho the further development of Occidental as well as Oriental astrology drew its resources from the primeval Assyrian, Babylonian, and Egyptian doctrines, yet from the second century, A.D., the astronomic work of Ptolemy and the exhaustive description of antique medicine by Galen derive their inspiration from Medicina Astrologica. Whatever these two great masters were able to report of the dependence of the functions of the body upon celestial bodies was from then on, without further inspection and examination, acknowledged to be true by the great majority of physicians. Only occasionally this or that practitioner is bold enough to oppose the intrusion of astrologic vagaries into the art of healing; among these radicals was the philosophically trained physician, Sextus Empiricus, who lived about the year 193, A.D. However, this protest of brave Sextus, as well as all subsequent ones, scarcely had any influence upon the astrological development of medicine. Astrology could not be arrested on its road to the domination of the world, and until the seventeenth century it controlled the thought of physicians with the same invincible sway that it exercised over the mental life of all other professions and classes. Medico-astrological superstition had become legalized, and this in spite of the fact that Galen himself at last expressed his distrust of the Medicina Astrologica, and at least endeavored to extenuate his part in its dissemination.
Let us now scrutinize more minutely the condition of Medicina Astrologica in the second century, A.D. The works of Ptolemy, the “Iatromathematica” of the mysterious Hermes Trismegistus, and the third book of Galen’s writing on the “critical days” furnish sufficient material for outlining the medico-astrological system of that period.
In the first place, the method by which the authors of that period instilled their astrologic dotage into the minds of their contemporaries varied considerably. Either astrological remarks were here and there interspersed in a work on medical or on astronomical subjects, as was the case, for instance, in the “Opus Quadripartitum” of Ptolemy and also in Galen’s book on the “critical days,” or astrology was treated as a special science in the form of a connected system, as is done, for instance, in the “Iatromathematica” of Hermes Trismegistus. Such textbooks of astrology obtained publicity in large numbers from about the fourteenth century on. Whoever may be inclined to cast a glance into the learned work of Sudhoff will be astonished to observe the extent to which iathromathematics flourished in the second half of the middle ages and at the turning-point of the Renaissance. Still another form was to impart to the public their astrological doctrines in the form of short sentences. We find nothing in such works regarding the intricate calculations and methods by which endeavors were made to fathom the language of the stars, but astrological results were communicated in concise, aphoristic sentences. This was done in the “Centiloquium” of Ptolemy, a work which in a hundred brief sayings brings an epitome of astrological wisdom to market. The work enjoyed the highest esteem in the middle ages. Such a book, therefore, would correspond to that form of modern literary production, which, under the title “Method of acquiring this or that accomplishment within a short period,” is advertised to us modern people in the daily press. Moreover, the “Centiloquium” of Ptolemy had many imitators. Such a work is found, for instance, in Arabic literature, and contains astrologic wisdom condensed into 150 brief sentences by the astrologer Almansor, who furnished the handbook upon request of his ruler; the Arabian, Bethem, has produced a similar work. We find analogous works appearing later in the middle ages. Eventually, the doctrines of astrology were put into neat rhymes; thus, for instance, Heinrich von Rantzau, who departed this life 1598 as governor of Schleswig-Holstein, celebrates in 100 well-turned verses the significance of the planets in relation to the physical and mental welfare of humanity. We shall again refer to this subject when considering astrology of the middle ages. The iatromathematic passages in the above-mentioned writings of Ptolemy, Hermes, and Galen furnished the foundation for all later astrologico-medical theories. For what the middle ages believed regarding the medical importance of the sidereal world, especially of the planets and the zodiac, was nothing but the immediate continuation, or elaboration, of the astrologic teachings of Ptolemy and other authors of the first Christian centuries.
In the first place, every portion of the human frame was placed under the influence of a certain celestial body.
The five planets already known to the ancients, as well as sun and moon, governed, according to Hermes, the following parts of the body:
The sun, the right eye.
The moon, the left eye.
Saturn, hearing.
Jupiter, the brain.
Mars, the blood.
Venus, taste and smell.
Mercury, tongue and gullet.
However, the influence which sun, moon, and the planets exercised upon the human body gradually became more intricate. It was no longer satisfactory to enumerate relations between the bodies of heaven and the human organs of such a general nature as given by the above table of Hermes. All parts and functions of the body were to be brought into the closest relations with the planets. Thus, for instance, the celebrated humanist, Marsilius Ficinus, the friend of the Medici (1433 to 1499), depicts most minutely in a book “On Life,” which was much read in its time, the relations between the body and the planets. This was also done by Heinrich von Rantzau, in his “Tractus Astrologicus,” which in its time was very celebrated. There we read regarding these conditions as follows:
Saturn governs the spleen, the bladder, the bones, the teeth, and, in part, the circulating juices of the body; causes the color of the skin of man to be dark yellowish; impedes or promotes growth; causes the eyes to be small, and prevents the growth of the beard.
Jupiter governs the lungs, the ribs, cartilages, the liver, arteries, the pulse, and the development of human semen; causes the white color of the skin, and gives a good figure.