particular circumstances, deserves in like manner to be attended to; and, if it be not of universal advantage, but useful in few instances only, it is still most worthy of estimation, and to be considered of no moderate value. Of this, the Ægyptians seem to have been well aware; their discoveries of the great faculties of this science have exceeded those of other nations, and they have in all cases combined the medical art with astronomical prognostication. And, had they been of opinion that all expected events are unalterable and not to be averted, they never would have instituted any propitiations, remedies, and preservatives against the influence of the Ambient, whether present or approaching, general or particular. But, by means of the science called by them Medical Mathematics, they combined with the power of prognostication the concurrent secondary influence arising out of the institutions and courses of nature, as well as the contrary influence which might be procured out of nature’s variety; and by means of these they rendered the indicated agency useful and advantageous: since their astronomy pointed out to them the kind of temperament liable to be acted upon, as well as the events about to proceed from the Ambient, and the peculiar influence of those events, while their medical skill made them acquainted with everything suitable or unsuitable to each of the effects to be procured. And it is by this process that remedies for present and preservatives against future disorders are to be acquired: for, without astronomical knowledge, medical aid would be most frequently unavailing; since the same identical remedies are not better calculated for all persons whatsoever, than they are for all diseases whatsoever.[28] The practicability and utility of prescience having been thus far briefly explained, the ensuing discourse must be proceeded with. It commences, introductorily, with an account of the efficient properties of each of the heavenly bodies, taken from the rules of the ancients, whose observations were founded in nature. And, first, of the influences of the planets and of the Sun and Moon. [28] This seems to explain the origin of the old alliance between medicine and astrology, so universally preserved until almost within the last century. CHAPTER IV THE INFLUENCES OF THE PLANETARY ORBS The Sun[29] is found to produce heat and moderate dryness. His magnitude, and the changes which he so evidently makes in the seasons, render his power more plainly perceptible than that of the other heavenly bodies; since his approach to the zenith of any part of the earth creates a greater degree of heat in that part and proportionately disposes its inhabitants after his own nature. [29] It will be recollected that the Ptolemaic hypothesis considers the Sun as a planetary orb, in consequence of his apparent progress through the zodiac.