About two years ago, in the course of some other experiments, it was noted that rats fed a diet low in minerals showed intestinal stasis,1 and this condition has been extensively studied since that time.
EXPERIMENTS ON RATS
Litters of rats which had just been weaned were divided into two groups. One half of each litter was fed an entirely adequate diet, and the other half was fed a diet low in minerals but otherwise complete. The composition of the two diets is shown in table 1, and it is evident that both of them contained sufficient carbohydrate, good protein, fat and vitamins A, D and B complex. It is not necessary to feed any vitamin C, as the rat can synthesize this substance. The Osborne and Mendel salt mixture2 contains reasonable amounts of all the essential minerals except copper, which was, however, present in the