(43)
The Physicians experience hereby as 'tis surer, so 'twill be greater.
He will make use of no Medicines but the choicest, and when they are in their full vigour, and such as are durable, and after once or twice Tryal of them, will seldom fail in his expected success; which cannot be certainly had without some tryal. For though a man buy the choicest ingredients, viz. Sena, which may appear to the Senses very good, yet he cannot positively say, how well, nor yet what quantity of it will work, till he hath made use of it. But afterwards he may confidently apply the whole parcel he hath bought to his purpose. The like may be instanced in a crop of Wheat or Barley, which the skillfullest Husband-man cannot tell how they will yield for Bread, or Malt, till he hath used them. Now how is it possible that a Physician can with any certainty make use of several Shops, since there is so great difference in the ingredients? and 'tis certain the same Medicine made by several Apothecaries, shall differ much in colour, smell, and tast, and consequently effect too; which cannot proceed from any other cause then the difference of the ingredients themselves, or by omitting some ingredients, or by substituting one thing for another; or by distinct ways of preparing them. The same also maybe said of Compositions, much more of Chymical Medicines so much sophisticated, and of so much danger and hazard, if not well prepared, which he cannot discover till he hath seen the effect of them, unless it be such as he makes himself, nor those neither till he hath made some tryal of them.
He will much inlarge Materia Medica, Chymistry
