“Quia est in eo virtus dormitava cujus est proprietas sensus assoupire.” Let us say likewise: the crushed herb calms the burning itch because it possesses a calming virtue whose property is to assuage itching. The quip is a good deal more philosophical than it looks. What do we know of our remedies or of anything? We perceive effects, but we cannot get back to their causes. In my village and for some distance around it, there is a popular belief that to relieve the pain of a Wasp’s or Bee’s sting all that we need do is to rub the part stung with three sorts of herbs. Take, they say, three kinds of herbs, the first that come to hand, make them into a bunch and rub hard. The prescription, by all accounts, is infallible. I thought at first that this was one of those therapeutic absurdities which have their birth in rustic imaginations. After making a trial, I admit that what sounds like a nonsensical remedy sometimes has something genuine about it. Friction with three kinds of herbs does actually deaden the sting of the Wasp or Bee. I hasten to add that the same success is achieved with a single herb; and so the result agrees with what the parsley and purslain have taught us in respect of the irritation caused by the Processionary. Why three herbs when one is enough? Three is the preeminently lucky number; it smacks of witchcraft, which is far from detracting from the virtues of the unguent. All rustic medicine has a touch of magic about it; and there is merit in doing things by threes. Perhaps the specific of the three herbs may even date back to the materia medica of antiquity. Dioscorides recommends τρίφυλλον: it is, he states, good for the bite of venomous serpents. To determine this celebrated three-leaved plant exactly would not be easy. Is it a common clover? The psoralea, with its pitchy odour? The menyanthes, or uck-bean, that inmate of the chilly peat-bogs? The oxalis, the wood-sorrel of the country-side? We cannot tell for certain. The botany of those days was innocent of the descriptive conscientiousness of ours. The plant which acted as a poison-antidote grouped its leaves by threes. That is its essential characteristic. Again the cabalistic number, essential to medical virtues as conceived by the first healers. The peasant, a tenacious conservative, has preserved the ancient remedy, but, by a happy inspiration, has changed the three original leaves into three different herbs; he has elaborated the τρίφυλλον into the threefold foliage which he crushes on the Bee’s sting. I seem to perceive a certain relation between these artless ways and the crushing of parsley as described by Réaumur. CHAPTER VII THE ARBUTUS CATERPILLAR