This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
"There is a general agreement that the physiological effects of medicinal substances upon man is the safest and most useful guide to their selection in diseased states. Excepting a few remedies whose uses have been established upon purely empirical grounds, and a very few others whose virtues depend upon chemical, antimicrobic or mechanical effects, this method is now generally used."6
The matter could not be better stated, whether the primary or secondary effects are desired, or if used in the indications for large or for small doses. In the section upon "Pharmacology," the question of determining the physiological actions by animal experimentation will be considered.
Since but one-sixth of the world-wide list of drugs are markedly toxic, and nearly half of the special American ones are in this category, are we carrying the determination of a drug by toxic physiological actions too far as regards its therapeutic employment? I don't believe we are.
Certainly the historical considerations narrated earlier in this "Introduction" show that the Old World loaded down botanic materia medica with hundreds of useless substances. What occasion is there for us to carry in the United States Pharmacopeia such substances as English chamomile, calamus, cassia, cusso, lappa, mezereum, rhus glabra, or sumbul? Why should the Homeopathic standards still include aethusa, cynapium, anagallis, bovista, carduus, erechtites, guaco, hypericum, laburnum, ocimum, polyporus, spiraea, or usnea? Why should the Eclectics worry along in this late day with adansonia, alstonia, arum, boldo, coto, damiana, hepatica, monesia, polypodium, sarracenia, or tril-lium?
These things, and many others, are dead - dead because the profession forgot them years ago, and they died of inanition. They simply fell down in practice, and they should be deleted from our literature.
Nevertheless, we should not be obsessed with the idea that because a botanic drug does not have a host of physiological, especially toxic, actions it is useless.
If some minor botanic drug does one thing superlatively well, we should preserve it for that one quality. Oil of chenopodium does kill the hookworm. What more can we ask? Emetine does kill amebae. Why expect it to be useful in a host of other things? Agar-agar has no physiological action whatever, yet it is a valuable mechanical laxative. Cotarnine arrests uterine hemorrhage in congestive conditions. Why expect it to be useful in post-partum hemorrhage? Filmaron, derived from male fern, kills the tapeworm; that is all. Why expect more of it? Phloridzin is a poor antiperiodic, but it is highly useful as a means for testing the functional activity of the kidney.
Some one or two defined purposes actually accomplished by a drug should include it in our lists; but a drug reputed to do fifty things, but none of them well, should be deleted, or so I believe.