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.
To the observations already made on this subject (vol. i., p. 96), I have to add that citric acid is specially indicated in those perhaps exceptional cases of rheumatism when the urine is alkaline, either from some peculiarity in the attack or from too prolonged use of alkali, and when depression is a marked symptom. In such a condition occurring together with bronchitis and valvular disease in a gouty subject I have seen lemon-juice given with some alcohol relieve after failure of alkalies, iodides, etc.
In Scorbutic Dysentery, lemon-juice was commended by Sir William Ferguson (Edinburgh Medical Journal, October, 1837), and for ammon-iacal urine by Dr. Bence Jones. I have used it in the latter condition, and found it serviceable.
Acidum citricum: dose, 10 to 30 gr., diluted and sweetened.
Sometimes tartaric or sulphuric acid.