is to be made in Nature. But many great Philosophers conceive Nature to be fuller of Intricacy, Difficulty, and Obscurity, then she is, puzling themselves about her ordinary actions, which yet are easie and free, and making their arguments hard, constrained, and mystical, many of them containing neither sense nor reason; when as, in my opinion, there is nothing else to be studied in Nature, but her substance and her actions. But I will leave them to their own Fancies and Humors, and say no more, but rest, Madam, _Your humble and_ _faithful Servant._ [1] Of the Disease of the Stone. _Ch._ 9. XV. _MADAM,_ Concerning Sympathy and Antipathy, and attractive or magnetick Inclinations, which some do ascribe to the influence of the Stars, others to an unknown Spirit as the Mover, others to the Instinct of Nature, hidden Proprieties, and certain formal Vertues; but your _Author_,[1] doth attribute to _directing Ideas, begotten by their Mother Charity, or a desire of Good Will_, and calls it[2] a _Gift naturally inherent in the Archeusses of either part_: If you please to have my opinion thereof, I think they are nothing else but plain ordinary Passions and Appetites. As for example: I take Sympathy, as also Magnetisme or attractive Power, to be such agreeable Motions in one part or Creature, as do cause a Fancy, love and desire to some other part or Creature; and Antipathy, when these Motions are disagreeable, and produce contrary effects, as dislike, hate and aversion to some part or Creature. And as there are many sorts of such motions, so there are many sorts of Sympathyes and Antipathyes, or Attractions and Aversions, made several manners or ways; For in some subjects, Sympathy requires a certain distance; as for example, in Iron and the Loadstone; for if the Iron be too far off, the Loadstone cannot exercise its power, when as in other subjects, there is no need of any such certain distance, as betwixt the Needle and the North-pole, as also the Weapon-salve; for the Needle will turn it self towards the North, whether it be near or far off from the North-pole; and so, be the Weapon which inflicted the wound, never so far from the wounded Person, as they say, yet it will nevertheless do its effect: But yet there must withal be some conjunction with the blood; for as your _Author_ mentions,[3] the Weapon shall be in vain anointed with the Unguent, unless it be made bloody, and the same blood be first dried on the same Weapon. Likewise the sounding of two eights when one is touched, must be done within a certain distance: the same may be said of all Infectious and catching Diseases amongst Animals, where the Infection, be it the Infected Air, or a Poysonous Vapour, or any thing else, must needs touch the body, and enter either through the Mouth, or Nostrils, or Ears, or Pores of the body; for though the like Antipathies of Infectious Diseases, as of the Plague, may be in several places far distant and remote from each other at one and the