particular proteid from which the necessary building stones can be split off in adequate number. It has been said, notably by Munk, that in dogs fed for some time on a low proteid diet there is a diminished power of absorption from the intestinal tract, associated with weakened digestion. If it is true that a lowered proteid intake results in a diminished utilization of the ingested food, that efficiency in the digestion and absorption of foodstuffs is impaired, it can only be interpreted as meaning that some injurious influence has been exerted on the epithelial cells of the intestine or the adjacent gland cells. We have, however, failed to find any evidence of deleterious action in the dogs that we have experimented with, where due regard was paid to maintaining a diet suitable for the physiological needs of the body. In the experiments that we have cited, both nitrogen intake and the fuel value of the food per day were lower than in Munk’s experiments, but the utilization of fat and proteid was not sensibly affected. The following tables give the results with ten dogs (including the six dogs already described) for lengths of time ranging from seven to twelve months, the periods indicated being each of ten days’ duration and occurring once each month. In the first table, the utilization of fat is shown, the figures given being based on determinations of the amount of fat contained in the excrement. Knowing the amount of fat in the daily food and the amount which passed through the intestine, it is easy to calculate the percentage of fat utilized. UTILIZATION OF FAT IN PERCENTAGES. +----------+-------------------------------------------------+ | | Dogs. | | Periods. +----+----+----+----+----+----+----+----+----+----+ | | 1 | 2 | 3 | 4 | 5 | 12 | 13 | 15 | 17 | 20 | +----------+----+----+----+----+----+----+----+----+----+----+ | 1 | 97 | 96 | 93 | 97 | 97 | 96 | 96 | 98 | 98 | 95 | | 2 | 96 | 96 | 98 | 98 | 98 | 94 | 95 | 97 | 98 | 95 | | 3 | 98 | 97 | 97 | 99 | 96 | 97 | 97 | 98 | 94 | 98 | | 4 | 98 | 96 | 97 | 97 | 96 | 94 | 95 | 98 | 97 | 97 | | 5 | 96 | .. | 94 | 98 | 97 | 95 | 95 | 98 | 97 | 96 | | 6 | 97 | 98 | 94 | 98 | 97 | 96 | 94 | 97 | 96 | 97 | | 7 | 97 | 98 | 98 | 97 | 96 | 93 | 95 | 97 | 98 | 96 | | 8 | .. | .. | 98 | 96 | 96 | 96 | 93 | 97 | .. | .. | | 9 | .. | .. | 98 | 97 | 98 | .. | 97 | 98 | .. | .. | | 10 | .. | .. | 98 | 97 | 98 | .. | .. | .. | .. | .. | | 11 | .. | .. | 97 | 92 | 97 | .. | .. | .. | .. | .. | | 12 | .. | .. | 97 | 97 | .. | .. | .. | .. | .. | .. | +----------+----+----+----+----+----+----+----+----+----+----+