During the last year I have had considerable experience with acidified milk, using either tenth normal hydrochloric or 75 per cent. lactic acid. Several interesting facts regarding hydrochloric acid milk, which were not present when lactic formulas were used, have been noticed. Among others, it was observed: first, that the mothers almost invariably stated that the child was urinating more frequently; second, that the urine was persistently acid, often to such an extent that the buttocks were excoriated.
With the idea in mind of obtaining more accurate knowledge of the exact metabolism of these two acids, the measurement of twenty-four hour urine output and the acid effect produced by each was undertaken.
Henderson and Palmer1 showed that the acid effect of any acid can be estimated by measuring the increase of titrable acidity and ammonia in the urine after the administration of the acid. The sum of these two