In another series of experiments the wounds were irrigated either by distilled water or by Wright's hypertonic solution. The wounds had previously been sterilised. After some hours' instillation the bacterial curve rose. Distilled water and the hypertonic solution produced similar results (Figs. 5 and 6). It was enough to substitute Dakin's solution for the hypertonic solution or the distilled water, and the curve descended, while the wound once more became aseptic. This experiment was frequently repeated, always yielding identical results.

FiG. 5.   Reinfection of a wound dressed for 24 hours with distilled water, (The wound is dressed with distilled water on the 17th; chlor araine is applied on the 18th.   Tr.)

FiG. 5. - Reinfection of a wound dressed for 24 hours with distilled water, (The wound is dressed with distilled water on the 17th; chlor-araine is applied on the 18th. - Tr.)

Fig. 6.   Reinfection of a wound dressed for 24 hours with hypertonic solution. (The hypertonic solution was applied on the 17th; Dakin's solution on the 18th.  Tr.)

Fig. 6. - Reinfection of a wound dressed for 24 hours with hypertonic solution. (The hypertonic solution was applied on the 17th; Dakin's solution on the 18th.- Tr.)

The action of M. Delbet's chloride of magnesium and of Dakin's solution were investigated under precisely similar conditions. The curve in Fig. 7 shows that a sterile wound whose surface was treated by the instillation of chloride of magnesium became rapidly reinfected. The number of microbes quickly became innumerable. An attempt was made to assist the action of the chloride of magnesium by washing the wound daily with neutral oleate of soda. The number of microbes diminished, but did not fall to zero. Directly the oleate of soda was discontinued the number of microbes again became innumerable. At this point the chloride of magnesium was replaced by Dakin's solution, and the number of microbes immediately fell to zero, as the curve indicates.

Fig. 7.  Intense infection of a wound treated with chloride of magnesium, afterwards sterilised by means of Dakin's solution

Fig. 7.- Intense infection of a wound treated with chloride of magnesium, afterwards sterilised by means of Dakin's solution.

These experiments show that distilled water, Wright's hypertonic solution, or Delbet's chloride of magnesium permit of the rapid reinfection of wounds previously aseptic, and that sterilisation is effected immediately these substances are replaced by an identical volume of hypochlorite of soda. It is therefore evident that the hypochlorite acts by virtue of its antiseptic power, not in a mechanical manner.

(c) The antiseptic power of hypochlorite is not due to its alkalinity. In M. Tissot's paper, read at l'Academie des Sciences by M. Dastre,1 that author attributed the action of hypochlorite of soda upon wounds to its alkalinity, and declared that the treatment to which Dakin had submitted it had the result of enfeebling its power! Although M. Tissot furnished in support of his opinion no precise observations, we have made experiments to test if the presence of an alkaline substance on the surface of a wound had any influence upon its bacteriological condition.

Upon a large surface wound on the external aspect of a limb, two squares of filter-paper of equal dimensions were placed. One of the squares was moistened with physiological saline solution, and the other with a solution of carbonate of soda, 0.5 per cent. Two days afterwards it was found that the number of microbes under the paper moistened with saline solution was almost identical with the number under the paper moistened with carbonate of soda. This experiment was repeated on other wounds with similar results. The alkaline solution had no more effect on the microbes present at the surface of a wound than had physiological saline solution.

2. Action of Hypochlorite on Microbial Toxins. - This point was considered in a course of experiments made by M. Auguste Lumiere.2 In a case of grave tetanus, he took some cubic centimetres of pus from a highly infected wound of the leg. This pus was divided into two equal parts, of which one was brought to double its volume by the addition of I per cent. solution of hypochlorite, and the other brought to the same volume by the addition of chloride of sodium solution, 0.8 per cent. After the lapse of an hour, I c.c. of each of these preparations was injected into guinea-pigs. It was found that the animals which had received the "control" pus died from tetanus in eight or ten days, whilst those in which had been injected pus with the addition of hypochlorite presented no symptoms of tetanus and survived.

1 Tissot, C. R. Academic des Sciences, Sept. 13, 1915.

2 Auguste Lumiere, C. R. Acadenie des Sciences, March 6, 1916.

This experiment was repeated with pus containing various microbes, streptococci, staphylococci, perfringens, etc. These preparations were administered to guinea-pigs by subcutaneous injection and to rabbits by intravenous. It was demonstrated that pus containing hypochlorite gave reactions either slight or benign, while the purulent fluids without added antiseptic produced evidences of infection, often ending in death.

M. Lumiere, in another series of experiments, candle-filtered pus both treated and not treated with hypochlorite, and injected animals with the filtrates. Filtrates of pus treated with hypochlorite produced no change in condition of the animals, while the filtrates from the control pus provoked pyrexia and emaciation. In short, these filtration products, placed in contact in vitro with leucocytes and microbes, demonstrate that phagocytosis is much more active when the pus has been treated with hypochlorite.