Of the various workers who have studied the effects of reduction of kidney substance, only Passler and Heineke record systematic blood-pressure observations. They were able to make direct measurements in the femoral on five dogs before and after operation, and reported a rise in pressure in all, the smallest increase being 15 mm., the greatest 29 mm., and the average 21.5 mm. These figures are based on the comparison of single readings before operation with one or more after operation, and are open to the objections I have previously urged. Because of the small number of reported observations in this field, I hope to be pardoned for presenting my still very incomplete studies at this time, in order that I may demonstrate one of the animals now living with reduced kidney substance and hypertension.I have made blood-pressure readings, by the rough method previously described, on twenty-three dogs, over a period of fifteen months. As a guide to normal readings in the dog I have figures from twelve dogs that ...