Note 295 — ON THE THEORY AND ART OF PRESCRIBING. (continued 2)

In some cases the subject to be pulverized has been previously exposed to heat, but the doubtful influence of exalted temperature upon vegetable bodies, ought to afford us a lesson of extreme caution; the astringency of the stalks of the Artichoke is entirely destroyed by being gently heated in an oven, for after this operation they no longer strike a black colour with the salts of iron: another example is afforded us in the effects of heat upon Starch, which is thus changed into a species of gum, no longer producing a blue colour with Iodine, and which is known in commerce under the name of “British Gum.”