This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
In this complaint, hydrochloric is often preferred to other acids, not because it has a more energetic effect than, e.g., sulphuric acid, but because it is better borne by the stomach. It is most reliable in cases that are due to abnormal fermentation in the bowels, with formation of lactic acid, as in what is called summer diarrhoea and gastric catarrh of infants; there are, however, many other remedies for this condition which must be considered better than the acid.
1 Manassein showed that in dogs made anaemic by blood-letting, the normal proportion of acid and pepsine was altered, and in such animals an addition of artificial acid to the gastric juice is, ceteris paribus, more effective than in the healthy (Virchow's Archiv, lv., p. 451).