While "all physicians should bow before the facts which he excels in discovering" (7/19.), he has also been able to make direct application of the marvels of entomology to some of the problems of hygiene and medicine. He has shown that the irritant poison secreted by certain caterpillars, "which sets the fingers which handle them on fire," is nothing but a waste product of the organism, a derivative of uric acid; he does not hesitate to perform painful experiments on himself in order to furnish the proof of his theory; and he explains thus the curious cases of dermatitis which are often observed among silkworm-breeders. (7/20.) He proves the uselessness of our meat-safes of metallic gauze, intended to preserve meat against contamination, and the efficacy of a mere envelope of paper, not only to preserve meat from flies, but also our garments from the clothes-moth. (7/21.) He recommends the curious Provençal recipe, which consists in boiling suspected mushrooms in salt and water before eating them. Finally he suggests to members of the medical profession that they might perhaps extract heroic remedies from these treacherous vegetables. (7/22.) He had need of that indefinite leisure which had hitherto been so wholly lacking, for the events of ephemeral lives occur at indeterminate hours, at unexpected moments, and are of brief duration. So, attentive to their least movements, Fabre goes forth to observe them at the earliest break of day, in the red dawn, when the bee "pops her head out of her attic window to see what the weather is," and the spiders of the thickets lie in wait under the whorls of their nets, "which the tears of night have changed into chaplets of dewdrops, whose magic jewellery, sparkling in the sun," is already attracting moths and midges. Seated for hours before a sprig of terebinth, his eye, armed with the magnifying glass, follows the slow manoeuvres of the terebinth louse, whose proboscis "cunningly distils the venom which causes the leaf to swell and produces those enormous tumours, those misshapen and monstrous galls, in which the young pass their period of slumber."