Handbook of medical entomology . twherever it goes it will prove a direct pest to man as well as to hisplants. Very soon after the introduction of the species there occurred inthe region where it had gained a foothold, a mysterious dermatitis ofman. The breaking out which usually occurred on the neck or otherexposed part of the body was always accompanied by an intense Nettling Insects 49 itching. It was soon found that this dermatitis was caused by certainshort, barbed hairs of the brown-tail caterpillars and that not only thecaterpillars but their cocoons and even the adult female moths migh
Handbook of medical entomology . twherever it goes it will prove a direct pest to man as well as to hisplants. Very soon after the introduction of the species there occurred inthe region where it had gained a foothold, a mysterious dermatitis ofman. The breaking out which usually occurred on the neck or otherexposed part of the body was always accompanied by an intense Nettling Insects 49 itching. It was soon found that this dermatitis was caused by certainshort, barbed hairs of the brown-tail caterpillars and that not only thecaterpillars but their cocoons and even the adult female moths mightharbor these nettling hairs and thus give rise to the irritation. Inmany cases the hairs were wafted to clothing on the line and when thiswas worn it might cause the same trouble. Still worse, it was foundthat very serious internal injury was often caused by breathing orswallowing the poisonous hairs. The earlier studies seemed to indicate that the irritation waspurely mechanical in origin, the result of the minute barbed hairs. 36. Browntail moths. One male and two females. Photograph byM. V. S. working into the skin in large numbers. Subsequently, however,Dr. Tyzzer (1907) demonstrated beyond question that the troublewas due to a poison contained in the hairs. In the first place, it isonly the peculiar short barbed hairs which will produce the dermatitiswhen rubbed on the skin, although most of the other hairs are sharplybarbed. Moreover, it was found that in various wa^^s the nettlingproperties could be destroyed without modifying the structure of thehairs. This was accompHshed by baking for one hour at iio^ C, bywarming to 60° C in distilled water, or by soaking in one per cent, or inone-tenth per cent, of potassium hydrate or sodium hydrate. Themost significant part of his work was the demonstration of the fact 50 Poisonous Arthropods
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsectp, bookyear1915
