E. canadensis gigantea (E. densa) and Nitella sp. were treated in test tubes with concns. of ethylene chlorhydrin and thiourea ranging from 10 to 0.025 gm. per liter, and the rate of streaming was recorded at 2-, 24-, and 48-hr. intervals. Concns. less than 10 gm. per liter of both chemicals cause a definite increase in the rate of streaming in Elodea and Nitella cells, after 24 hrs.'' treatment. The maximum rates of streaming were produced by a solution of 0.1 gm. per 1. of ethylene chlorhydrin in Elodea, and of 0.25 gm. per 1. in Nitella; and by a solution of 0.1 gm. per 1. of thiourea in Elodea and in Nitella. The max. increase in rate of streaming averaged 70-100% above readings from the controls in water.