THE CAUSATIVE FACTOR IN THE PRODUCTION OF THE DERMATITIS OF GROUND ITCH (UNCINARIASIS).

In studying the inflammation produced by the larvæ of the Uncinaria americana in their passage through the skin, the question arose as to whether the mechanical irritation produced by the presence of the larvæ would account for the vesicular eruption and the intense swelling of the tissues. As previously reported,¹ it was noticed that the eruption of ground itch, while very angry looking, showed very little tenderness on pressure, but was accompanied by an excruciating itching, and the inflammation did not appear to be due to bacterial infection. After considering the eruption and the accompanying symptoms, it appeared that possibly the eruption, the swelling and the intense itching might be due to some substance secreted by the larvæ and poured out into the skin. If such a substance were excreted, might it be present in the bodies of the larvæ before they begin to make their way into the