Does a given quantity of any medicinal agent produce under similar conditions approximately the same therapeutic or toxic effects? There can be but one answer to this question, and that an affirmative one. Granted that individual susceptibility shows surprisingly wide variations, and that vital reactions are profoundly modified by accidental causes, not always obvious, it remains true that from a certain dose of any potent drug we expect to obtain certain definite results, which we regard necessary for the restoration of our patient to a normal status.
It is true that in adjusting the dose in each particular instance, we take into account the factors of age, sex, general physical condition and known idiosyncrasy on the part of the patient; the very fact that we do this places emphasis on our conviction that a given dose will produce in a normal subject reactions of a definite known kind and degree.
LYONS AB. STANDARDIZATION OF CRUDE DRUGS AND GALENICAL PREPARATIONS.. JAMA. 1902;XXXVIII(1):17-21. doi:10.1001/jama.1902.62480010017001f