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.
Boinet gives the history of a chronic abscess occupying the whole right iliac fossa; it followed a bubo, and discharged profusely by a fistulous tract. After many months of unsuccessful treatment by injections, ointments, nitrate of mercury, potash, compression, etc., he injected a solution of iodine (2 dr. of tincture in 4 oz. of water) to the bottom of the cavity through a catheter; much pain followed, and afterward severe febrile reaction, but in about a fortnight radical cure was obtained (Iodo-therapie). Such successful results cannot be always depended upon, and, in fact, I have known injury from this mode of treatment in many such cases; for instance, in one case of psoas abscess, an injection containing 1 dr. of tincture in 3 oz. of water was practised three times in a fortnight, but considerable irritation and increase of hectic was set up without subsequent improvement; after an interval of four months it was repeated
(1 dr. in 4 oz.), but with the same result, and the patient died shortly afterward; vertebral caries was found, but only slight in amount.
In another similar psoas abscess, where the malady was not recognized until an opening in the groin had nearly occurred, iodine was injected, and induced much hectic and aggravation of symptoms; no improvement could be traced to repeated injections, but the patient is still living.
In smaller abscesses I have found the injection of iodine beneficial; it offers less risk than in large psoas abscess, and is more likely to succeed. Mr. Stirton found it answer well in a chronic scrofulous abscess of the groin - he used 2 gr. to 1 oz. of water (Medical Times, ii., 1870).