322              Important Helminth Parasites of Horses

microfilariae. The microfilariae in Lichen tropicus are never found in the
blood of the affected animals. The adult worms of the larvae associated
with these two conditions are not yet definitely known. No satisfactory
treatment for these two conditions is known. Sub-toxic doses of arsenious
acid; intravenous administration of neo-arseno-phenamine; potassium
antimony tartrate and sodium antimony tartrate are not beneficial in the
treatment of Lichen tropicus.

The author is grateful to the Offg. Director, Mr. J. R. Haddow, B.Sc.,
M.R.C.V.S., D.V.S.M., I.V.S., for kindly going through the manuscript and
offering some useful suggestions. He is indebted to Drs. Schwartz, Imes
and Wright for the illustrations in this article.