A Dakin s Hypochlorite Of Soda 2A Dakin s Hypochlorite Of Soda 3A Dakin s Hypochlorite Of Soda 4Fig. 1.   Four fragments of skin of identical dimensions were placed in chlor amine (4), hypochlorite of magnesium (3), Dakin's hypochlorite (1), and electrolytic hypochlorite (2). Results at the end of 48 hours.

Fig. 1. - Four fragments of skin of identical dimensions were placed in chlor-amine (4), hypochlorite of magnesium (3), Dakin's hypochlorite (1), and electrolytic hypochlorite (2). Results at the end of 48 hours.

Many other preparations of hypochlorites have been previously employed in surgery. Eau de Javel and Labarraque's solution are well known, as well as the hypochlorites of calcium, potassium, and magnesium. Since the beginning of this war, eau de Javel has been used with good results. In November, 1914, in the hospital at Dunkirk, MM. Landry and Jacomet made successful use of eau de Javel in "gas" infections.

But eau de Javel is dangerous, for its strength in hypochlorite is variable in the extreme, and it always contains an amount of alkali which renders it caustic. The alkali contained in eau de Javel and in Dakin's solution when badly prepared is responsible for the secondary haemorrhages which have sometimes been observed as a result of their employment in the neighbourhood of the blood-vessels.

Hypochlorite of magnesium has been employed with success by M. Dubard. Its bactericidal power is similar to that of sodium hypochlorite, and it is not irritating. Dakin, however, elected to employ the hypochlorite of sodium rather than the magnesium salt, because the solvent power of the former, in the case of mortified tissues, is greatly superior to that of the latter, and because the efficacy of an antiseptic depends to a certain extent upon its ability to cleanse the surfaces of wounds. Daufresne placed fragments of skin of equal dimensions in solutions of magnesium hypochlorite and sodium hypochlorite. Another fragment of skin, placed in chloramine, served as a "control." While the fragment of skin immersed in Dakin's solution shrank to about one-third of its original size, the fragment placed in the magnesium solution underwent a very much less considerable change (Fig. 1).

Mixtures of powdered chloride of lime and boric acid have been employed by Vincent, Lumiere, and Lorrain Smith. The local production, by an admixture of powdered hypochlorites, of hypochlorous acid or chlorine in a comparatively high degree of concentration, is more dangerous to the healthy tissues than the continued application of a weak and neutral solution of hypochlorite of sodium. Moreover, a solution possesses the advantage of penetrating into all the recesses of deep wounds. Vincent's powder, injected into anfractuous wounds, falls upon the coagulum, but does not reach the surface of the wound. It may also form upon the surface of the tissues a crust which protects the bacteria from the antiseptic substance. In this manner serious infections may develop subsequently to the application of Vincent's powder to deep wounds. Moreover, it is impossible in one operation to introduce into a wound a sufficient quantity of antiseptic to sterilise it. To achieve this end the concentration of the active substance would require to be very great, and, consequently, dangerous to the tissues.

Generally speaking, the experiments we have carried out with Dakin, by means of powdered substances, and substances dissolved in fatty matters, such as vaseline or lanoline, have yielded results greatly inferior to those of the experiments made with watery solutions:

1. Bactericidal Action of Dakin's Solution. - The bactericidal action of Dakin's solution of hypochlorite of soda has been studied by Daufresne, using micro-organisms suspended in water, and in water with the addition of horse-serum. Staphylococci in suspension in water are killed in two hours by hypochlorite of a strength of 1: 500,000 to 1: 1,000,000; whilst, in the presence of horse-serum, the concentration increases, and should be I: 1,500 to 1:2,000. Streptococci are killed more rapidly. B. pyocyaneus in suspension in water is killed in two hours by a strength of 1: 100,000 to 1: 1,000,000; whilst in presence of horse-serum a strength of 1: 2,500 to 1:5,000 becomes necessary. In the experiments made on mixtures of pus and hypochlorite, it is found that sterilisation generally takes place when two or three volumes of hypochlorite to one volume of pus are used. The action of hypochlorite naturally varies according to the character of the pus.

The results of these experiments in vitro are of but slight importance, for experimental conditions vary too greatly from the actual. In wounds, in fact, a small quantity of pus is found in contact with a large quantity of antiseptic, because the solution of hypochlorite is constantly being renewed. In the experiments in vitro, the duration of the action of the hypochlorite upon the microbes in suspension in the pus is short. If, at the end of two or three hours, one tests for the hypochlorite contained in the mixture, sometimes it is found that it has completely disappeared. The hypochlorite,in fact, rapidly enters into combination with the proteins of the pus, and chemical analysis is no longer able to discover it. It (00 denotes infinity. Translator.) is precisely because of this rapid disappearance of hypochlorite when in contact with secretions, that Dakin's solution should be continuously instilled into wounds, or if intermittently, at short intervals. Ignorance of this chemical property of the hypochlorites has led surgeons to be surprised that mixtures of pus and hypochlorite kept in the incubator for several hours should become favourable breeding-grounds for microbes. It is quite evident that, after being treated in this manner, the mixture contains hypochlorite no longer. When a solution of hypochlorite is employed, it is essential to determine the quantity of the active substance contained in the solution before and after the test.