On account of the occasional incidence of goitre and death of lambs produced on the experiment station farm, an experiment on the administration of potassium iodide to the pregnant ewes was carried on in 1917-18. Three lots of four on the same ration were fed from 2 to 15 grains potassium iodide daily. Results on the prevention of goitre in the young were not conclusive, but the passage of the iodine into the milk of the ewes was demonstrated, and pronounced unfavorable results from too large a dose of iodine were obtained, especially in the lots receiving the larger allowances. These unfavorable effects were not particularly in the vigor of the new-born and the lack of resistance to disease