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.
Dr. Curtin has recorded that a severe epidemic in an institution under his direction ceased within twelve hours after the inmates were treated freely with "sulphuric acid lemonade" - the only fresh case occurring in a man who refused to take the medicine. Two days after it was discontinued two new cases appeared, and an epidemic threatened, but was again stayed by the acid, and in the surgical wards, where the acid was used from the first, no case appeared, while every other part of the institution suffered more or less (Philadelphia Medical Times, iii., p. 649). This experience makes it desirable under similar circumstances to adopt the same method as prophylactic.