The tests were made with sodium carbonate in concentrations varying from 0.2 to 1.0 per cent, and in varying quantities. In concentrations of 0.2 per cent or less the sodium carbonate solution appears to have the same influence on the hunger contractions as equal quantities of water, that is, a slight temporary inhibition. This inhibition is evidently due, not to the alkalinity, but to the bulk of the solution. In concentrations of 0.2 per cent to 1.0 per cent the degree of inhibition produced is on the whole directly proportional to the concentration and the quantity of the solution put into the stomach; 200 c.c. of 1 per cent sodium carbonate causes about the same degree of inhibition as 200 c.c. ? per cent hydrochloric acid. It is thus clear that alkalinity has the same effect as acidity, only to a less degree, both acids and alkalies causing inhibition without any after-effect of the nature of augmentation.
The fact that 0.2 per cent sodium carbonate has no more effect on the hunger movements than equal quantities of water seems to show that a slight alkalinity of the gastric mucosa is compatible with the hunger contractions of the empty stomach. It makes it also evident that the entrance of bile or intestinal juice into the stomach will have little or no effect on these movements, while any concentration that influences these movements produces inhibition.