Astronomy, (from a star, and law). It is the science which teaches the knowledge of the heavenly bodies, showing their magnitudes, distances, order, and motion. Hippocrates says, that one ignorant of astronomy cannot be well qualified for a physician. Others, since his days, have greatly extolled the utility of this science in the study and practice of medicine; some styling anatomy the right eye of physic, and astronomy its left: for, they say, such is the influence of the sun, moon, and stars, especially the planets, upon terrestrial bodies, by the intervention of the ether and atmosphere, that they induce very sensible changes in them; but admitting some influence in the planets, it is in a degree too trifling to affect the practice of medicine. The planets may influence our atmosphere, and perhaps in some slight degree our bodies; but meteorology, and those branches of science by which we are taught the nature and properties of the air, seem more directly proper to medical enquiries.

It is pleaded, that the aspects of the stars influence the human body, because in the vernal equinox, or the summer solstice, the force of- intermitting fevers is destroyed, though obstinate in all other seasons; and because that the equinoxes are peculiarly hurtful to some patients; but these circumstances are better accounted for on principles less remote than those derived from astronomy. The late Dr. Mead was a great advocate for this branch of science; and Dr. Balfour has more lately endeavoured to show the connection of the access or crisis of fevers with the solar and lunar conjunctions. This connection is not observable in these climates, but its existence cannot be wholly denied in the tropical regions.