1.Thirteen soldiers were treated with tetrachlorethylene in doses of 0.5 and 1.5 cc. and thirteen with a 2 to 1 combination of tetrachlorethylene and oil of chenopodium in doses of 1.5 and 2.4 cc. Efficiency rates of such dosages were calculated for species and sex on the basis of per cent removed by first treatment as tested by the administration of 3 cc. of oil of chenopodium.
2.Comparative results presented for tetrachlorethylene and carbon tetrachloride given in equal doses and under similar conditions show that carbon tetrachloride alone or in combination with oil of chenopodium is more efficient for Necator than is tetrachlorethylene and that in combination with oil of chenopodium, carbon tetrachloride is more efficient than is tetrachlorethylene for Ancylostoma. When given alone such superiority of carbon tetrachloride for Ancylostoma is not apparent but the Ancylostoma infestation of the cases studied was very low: this result should be checked against work done in areas of heavy Ancylostoma infestation.
3.Tetrachlorethylene is definitely more effective against Necator than against Ancylostoma and is probably slightly more effective against females than against males of the same species. The decreasing order of resistance to a 2 to 1 combination of tetrachlorethylene and oil of chenopodium was found to be the same as that for a 2 to 1 combination of carbon tetrachloride and oil of chenopodium, viz.
4.From the present study it would appear that tetrachlorethylene offers no advantages over carbon tetrachloride in the treatment of hookworm disease in Paraguay, where the infestation is largely (93 per cent) Necator. Further tests for toxicity and anthelmintic efficiency should be made in areas of heavy Ancylostoma infestation to determine whether tetrachlorethylene is superior to carbon tetrachloride for use in such areas.