In chronic cases, provided a free opening is secured, an iodine injection (1 to 2 dr. of tr. in the pint) is sometimes serviceable, both to disinfect and to stimulate healthier secretion and contraction of the cavity, and many patients have, doubtless, recovered under its use. Dr. Dickinson speaks of it as better than any other treatment in his experience (British Medical Journal, 1876). On the other hand, I have myself known it excite much undue irritation, both local and systemic. In some cases, sudden or nearly sudden death has followed the injection of iodine solutions into the pleural cavity; but we cannot reasonably attribute the result to iodine, because in the very same cases iodine had been previously used without harm, and besides, sudden death has followed, in a similar manner, the injection of warm water, of carbolic acid lotion, etc. The effect may have been connected, rather, with mechanical conditions, such as insufficient freedom of exit, too great pressure of fluid, etc., or else with special cardiac conditions of feebleness, dilatation, etc., but certainly, I am strongly of opinion that injections into the pleural cavity are never without some risk, and can seldom be practised safely; they should be discontinued in favor of free drainage with strict antiseptic precautions.

A little of the solid iodine, placed in perforated chip-boxes in or near the bed, forms a good disinfectant in cases of foul wounds, discharges, etc.