Numerous cases of opthalmia nodosa are on record. Of those from this country, one of the most interesting is reported by de Schweinitz and Shumway (1904). It is that of a child of fifteen years whose eye had become inflamed owing to the presence of some foreign body. Downward and inward on the bulbar conjunctiva were a number of flattened, grayish-yellow nodules, between which was a marked congestion of the conjunctival and episcleral vessels (fig. 41_a_). Twenty-seven nodules could be differentiated, those directly in the center of the collection being somewhat confluent and assuming a crescentic and circular appearance. The nodules were excised and, on sectioning, were found to be composed of a layer of spindle cells and round cells, outside of which the tissue was condensed into a capsule. The interior consisted of epithelioid cells, between which was a considerable intercellular substance. Directly in the center of a certain number of nodules was found the section of a hair (fig. 41_b_). The evidence indicated that the injury had resulted from playing with caterpillars of one of the Arctiid moths, _Spilosoma virginica_. Other reported cases have been caused by the hairs of larvæ of _Lasiocampa rubi_, _L. pini_, _Porthetria dispar_, _Psilura monacha_ and _Cnethocampa processionea_. [Illustration: 41_b_. Section through one of the nodules showing the caterpillar hair. De Schweinitz and Shumway.] RELIEF FROM POISONING BY NETTLING LARVÆ--The irritation from nettling larvæ is often severe and, especially in regions where the brown-tail abounds, inquiries as to treatment arise. In general, it may be said that cooling lotions afford relief, and that scratching, with the possibilities of secondary infection, should be avoided, in so far as possible. Among the remedies usually at hand, weak solutions of ammonia, or a paste of ordinary baking soda are helpful. Castellani and Chalmers recommend cleaning away the hairs by bathing the region with an alkaline lotion, such as two per cent solution of bicarbonate of soda, and then applying an ointment of ichthyol (10%). In the brown-tail district, there are many proprietary remedies of which the best ones are essentially the following, as recommended by Kirkland (1907): Carbolic acid ½ drachm. Zinc oxide ½ oz. Lime water 8 oz. Shake thoroughly and rub well into the affected parts. In some cases, and especially where there is danger of secondary infection, the use of a weak solution of creoline (one teaspoonful to a quart of water), is to be advised. VESCICATING INSECTS AND THOSE POSSESSING OTHER POISONS IN THEIR BLOOD PLASMA