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.
Bretonneau recommended the application of the strong acid mixed only with a little honey to the false membranes and adjacent tissues, and this has sometimes arrested the local progress of the malady; but, on the other hand, it has sometimes done harm by exciting irritation, which has favored the development of membrane. A weaker solution, such as the dilute acid of the Pharmacopoeia (1 in 3 1/4), is to be preferred, and much advantage has been traced to it (Dr. Heslop: Medical Times, i., 1858, p. 612). A weaker gargle (1 or 2 dr. in 8 oz.), as above mentioned, may be used if the conditions admit.