Strictly speaking, every poison consisting of assimilable elements may be considered as unwholesome food.  It is rejected by the stomach, or it produces diarrhoea, or it causes vertigo or disturbance of the heart’s action, or some other symptom for which the subject of it would consult the physician, if it came on from any other cause than taking it under the name of medicine.  Yet portions of this unwholesome food which we call medicine, we have reason to believe, are assimilated; thus, castor-oil appears to be partially digested by infants, so that they require large doses to affect them medicinally.  Even that deadliest of poisons, hydrocyanic acid, is probably assimilated, and helps to make living tissue, if it do not kill the patient, for the assimilable elements which it contains, given in the separate forms of amygdalin and emulsin, produce no disturbance, unless, as in Bernard’s experiments, they are suffered to meet in the digestive organs.  A medicine consisting of assimilable substances being then simply unwholesome food, we understand what is meant by those cumulative effects of such remedies often observed, as in the case of digitalis and strychnia.  They are precisely similar to the cumulative effects of a salt diet in producing scurvy, or of spurred rye in producing dry gangrene.  As the effects of such substances are a violence to the organs, we should exercise the same caution with regard to their use that we would exercise about any other kind of poisonous food,—­partridges at certain seasons, for instance.  Even where these poisonous kinds of food seem to be useful, we should still regard them with great jealousy.  Digitalis lowers the pulse in febrile conditions.  Veratrum viride does the same thing.  How do we know that a rapid pulse is not a normal adjustment of nature to the condition it accompanies?  Digitalis has gone out of favor; how sure are we that Veratrum viride will not be found to do more harm than good in a case of internal inflammation, taking the whole course of the disease into consideration?  Think of the change of opinion with regard to the use of opium in delirium tremens (which you remember is sometimes called delirium vigilans), where it seemed so obviously indicated, since the publication of Dr. Ware’s admirable essay.  I respect the evidence of my contemporaries, but I cannot forget the sayings of the Father of medicine,—­Ars longa, judicium diffcile.

I am not presuming to express an opinion concerning Veratrum viride, which was little heard of when I was still practising medicine.  I am only appealing to that higher court of experience which sits in judgment on all decisions of the lower medical tribunals, and which requires more than one generation for its final verdict.