3. At the same time dissolve, cold, in the five other liters of water the sodium carbonate and the bicarbonate.

4. Pour all at once the solution of the sodium salts into the jar containing the maceration of chlorinated lime, agitate vigorously for a few moments, and leave it quiet to permit the calcium carbonate to settle as it forms. At the end of half an hour, siphon the liquid and filter it through double paper to obtain an entirely limpid product, which must be protected from light.

Titration Of Dakin's Solution

It is wise precaution to verify, from time to time, the titer of the solution. This titration utilizes the same material and the same chemical substances as are used to determine the active chlorine in the chlorinated lime:

Measure out 10 c.c. of the solution, add 20 c.c. of 1: 10 solution of potassium iodid, and 2 c.c. of acetic or hydrochloric acid. Drop, a drop at a time, into this mixture a decinormal solution of sodium thiosulphate until decoloration is complete. The number of cubic centimeters employed multiplied by 0.03725 will give the weight of the sodium hypochlorite contained in 100 c.c. of the solution. A solution is correct when, under the conditions given above, from 12 to 13 c.c. of decinormal thiosulphate are required to complete the decoloration: 13 X 0.03725 = 0.485 per cent. of NaOCl.

The Test For The Alkalinity Of Dakin's Solution

Pour into a glass about 20 c.c. of the fluid, and drop on the surface a few centigrams of phenolphthalein in powdered form. Dakin's solution, correctly prepared, gives absolutely no change in tint.

It is to be noted that the solution must be of reasonable freshness, exactly neutral, and absolutely of a concentration between 0.45 and 0.50 per cent. The tubes must be so placed that the liquid runs down and not up into the wound, and must be so arranged as to bring and keep the liquid in contact with every part of the wound surface. To insure continuous contact and to hold the tubes in place fluff gauze is stuffed between the tubes. The antiseptic is rapidly taken up by the tissues, so its renewal is secured by an instillation of the liquid every two hours. At no time is enough solution allowed to run in to more than fill the wound and saturate the packing. The method is neither one of drainage nor of irrigation, nor a continuous drip process, for no liquid flows except during the two-hourly instillations. The skin for 3 or 4 inches on all sides is protected by a covering of bandage gauze impregnated with sterile petrolatum or vaseline. As the solution can dissolve dead tissue, clots, etc., all vessels must be tied off, otherwise there may be secondary hemorrhage.

Pain is an indication that the solution is not right, or if during the instillation, that the liquid is being allowed to run in under too much pressure.

This liquid not only forms chloramins as described above of a disinfectant value 14 to 22 times that of phenol, but, in addition, through its hypertonicity induces a flow of lymph from the wound surfaces and so prevents any absorption of toxic products through the lymph-channels. In the Dakin-Carrel treatment the absence of lymphatic involvement is striking.

Dichloramin-T

This is toluene parasulphondichloramin, an antiseptic prepared by Dakin to do away with the difficulties of the technic and the care required in the Dakin-Carrel treatment. It is employed in 7.5 per cent. solution in chlorinated eucalyptol and chlorinated liquid petrolatum. The oils are chlorinated so that they will not take up the chlorine of the antiseptic, and they liberate the antiseptic slowly and continuously for a period of eighteen to twenty-four hours. Dichloramin-T corresponds with the >Nc1 substances formed when Dakin's solution is brought in contact with the exudate of wounds. It is non-irritant to the skin or in the wound, and, according to Dakin, is as effective a germicide as iodine without its destructive effect. Like Dakin's solution, dichloramin-T can dissolve dead tissue and clots, so all hemorrhage must be stopped by ligation.

Chlorazene is a proprietary preparation of the sodium salt of toluene parasulphochloramin, a non-irritant germicide four times the strength of phenol and used in 2 per cent. solution.

Bromine is a reddish-brown, corrosive liquid, the fumes from which are very irritating to the respiratory passages. Severe bronchitis and laryngitis have occurred from the breaking of a bottle of bromine or its use in the laboratory. For bromine burns the best antidote is phenol, which forms the comparatively harmless tribromphenol. Bromine water is employed as a gargle.

Iodine is used in the form of the tincture of iodine (iodine, 7 per cent.; potassium iodide, 5 per cent.) in the treatment of ring-worm and other parasitic skin diseases. This tincture or an alcoholic solution free from potassium iodide has recently come into extensive use as a skin disinfectant preliminary to operation. It is highly convenient in preparing the skin for paracentesis and small cuts, and for major surgery. It does not injure the skin, and its staining soon disappears. Experiments have shown it to have an almost instantaneous destructive effect upon the Staphylococcus albus of the skin as well as on other bacteria. The work of Post and Nicoll (see Table), Kinnaman, and many others has established its positive disinfectant value in surgery. Kinnaman found that a 1: 100 iodine solution destroyed the Bacillus tuberculosis in seven minutes, and Bacillus prodigiosus and anthrax bacillus with spores in ten minutes. Lambert found that among a number of antiseptics iodine was the only one to which animal cells were more resistant than staphylococci. Churchill's tincture (16.5 per cent. of iodine) is also employed, but such strong solutions are not necessary. E. McDonald recommends a 2 per cent. solution in carbon tetrachloride.

The antiseptic iodine compounds are iodoform and certain iodine-containing compounds of the phenol group, viz., thymol iodide (aristol), europhen and losophan, which are cresol compounds, and iodol (tetra-iodo-pyrrhol). These were designed to have the iodoform antiseptic effect without its disagreeable odor, but they do not act like iodoform, and are probably antiseptic because of their phenol affinities rather than because of their iodine constituent. Their antiseptic value cannot, therefore, be judged by their iodine percentage.

Iodoform is a yellow, crystalline powder, insoluble in water, and with a disagreeable, persistent, and penetrating odor. It is not germicidal except in contact with raw tissues or wound secretions, where part of it is believed to change into iod-albumi-nates and di-iodo-di-acetylene. Locally it is irritant and may cause a dermatitis or a pustular rash. After absorption it may have simply the action of an iodide, or give poisonous symptoms which indicate the presence of unchanged iodoform in the blood. Iodoform poisoning usually manifests itself in one of three forms, the prominent symptoms being - (1) Vomiting; (2) cerebral excitement and delirium; or (3) cerebral depression with melancholia. In each case the outcome may be coma and collapse. The poisoning is usually due to the packing of large cavities with strong iodoform gauze. The symptoms of hyperthyroidism have been reported. In tuberculous sinuses and in the peritoneal cavity in tuberculous peritonitis, a mixture of iodoform, glycerin, and ether, incorrectly called "iodoform emulsion," seems to be of benefit; though the belief that iodoform exerts a specific effect upon the tubercle bacillus has no experimental support. It has also been thought to have a special value in infections by the Bacillus pyocyaneus. To remove the odor of iodoform from the hands Ricketts recommends vinegar.