not somehow connected with a distorted observation or explanation of nature. However interesting these considerations may be, we can not here pursue them any further. Such investigations belong to the history of superstition in general, and any one who desires more detailed information is referred to the enormous literature of the subject. We can here consider only those relations which prevail, or have prevailed, between superstition and natural science, and principally the influence which was thus exerted upon the art of healing by astronomy. Astronomy and medicine became most intimately connected during the earliest periods of human civilization. The literature of cuneiform inscriptions shows us that the attempt to bring the stars into connection with human destinies is primeval, and reaches back to the ancient Babylonian age, even to the Sumero-Accadic period (Sudhoff, _Med. Woche._ 1901, No. 41). How primeval peoples came to connect their destinies with the heavenly bodies and their orbits is explained so lucidly by Troels-Lund (page 28, etc.) that we shall cite his descriptions, even if they are rather long for quotation. He says: “The Chaldean history of creation is inscribed upon seven clay tablets. On the fifth tablet we read: ‘The seventh day He instituted as a holy day, and ordained that man should rest from all labor.’ Why just seven? Because the holy number seven of the planets imperceptibly shone through the work of creation, and was imperceptibly impressed upon the entire order of thought. We are here at the decisive epoch at which the planets for the first time gave an impetus to human conception, the effects of which were to persist for thousands of years. This was repeated a second time when Copernicus, in dealing especially with the orbit of the planets, founded the still-prevailing conception of the universe.