In order to satisfy the astrological requirement of the physician most thoroughly, there arose in the middle ages a very peculiar literature. Under the name of an almanac or calendarium, thick folio volumes appeared, which enumerated, in long tables, the various positions of the planets and of the signs of the zodiac, so that the astrologer was enabled to note the fate of mankind rapidly and easily. The contents of such calendaria are beyond description. Apart from remarks which referred to all occurrences of civil life, was stated the exact period when to have the hair cut, when venesection was to be performed, when to draw teeth, when to take a bath, etc. Even the proper time for prayer was indicated by such a calendarium. According to the experience of Peter of Abano, the conjunction of the moon with Jupiter in the Dragon was sure to effect an answer to prayer. Hieronymus Cardanus had discovered, with the aid of astrology, that a request was sure to be complied with if a prayer was offered to the Virgin Mary on the first day of April, at 8 A.M. (Möhsen, Vol. II., page 423). Physicians excelled in the compilation of such calendaria, especially during the fifteenth and sixteenth centuries. Professors, forensic physicians, surgeons—in fact, all representatives of medical art—were equally intent upon instructing the public by calendaria in regard to the most various branches of _Medicina Astrologica_; thus, for instance, David Herliz, physician at Prenzlau, supplied Pomerania, Mecklenburg, and the Margravate of Brandenburg with calendars for fifty years, from the year 1584. The Marburg professor of medicine, Victorinus Schönfelder, played a similar rôle during the same period for western Germany. The physician, as almanac-maker, is probably one of the most wonderful results of medical superstition, and this aberration of medicine clung so firmly to the people that, even in the eighteenth and nineteenth centuries, certain days of the year were considered as especially favorable for venesection, and the calendars took particular pains to call the attention of the public most emphatically to good days for blood-letting. [Illustration: FIG. 5—VENESECTION IN ITS ASTRONOMICAL CONNECTION] =Explanation of Fig. 5= _A._ The astronomic signs which are noted on the different parts of the body indicate the signs of the zodiac, under the special influence of which the respective members of the body are said to be. _B._ The numerals which are found at the most varied parts of the body refer to indications for venesection, as stated below. In these localities, which are characterized by figures, blood was drawn for the most various affections, namely in: 1. Pains of the eyes and head; affections of the face, including eruptions. 2. Affections of the head; mental disturbances. 3. Affections of the eye of various kinds. 4 and 5. Pains in the ears; lachrymation. 6 and 7. Tinnitus aurium; tremor of the head.