Feeding sodium chloride in gelatin capsules to brook trout caused a rise in blood salt when amounts of 10, 15, 20, and 25 milligrams were ingested. No effect on the chloride level was found when 5 milligrams were fed. An edema resulted from feeding the two higher levels. This disappeared in the 20 milligram experiment with no loss of fish, but caused a mortality in the 25 milligram level. The absorption curves for salt were similar to those described for carbohydrates. Excretion curves were found to be curvilinear, but showed a break in the two higher levels with the appearance of edema. It was necessary to feed between 0.91 and 1.82 grams of salt per kilogram of body weight to produce a rise in blood salt and between 2.72 and 3.64 grams per kilogram to cause an edema.