Dakin et al.[7] arrived at a similar conclusion from a consideration of the results obtained during the use of hypochlorite solutions in the treatment of wounds by Carrel's method of irrigation. They attributed the marked beneficial action to the formation of chloramines _in situ_ by the action of hypochlorous acid upon amino acids and proteid bodies. Compound chloramines (chlorinated aminobenzoic acids) were prepared in the laboratory and found to give excellent results in reducing wound infection. Later, other compounds were prepared for the purpose of sterilising small quantities of water for the use of mobile troops (see p. 128). Rideal[6] was the first to note the strong germicidal power of chloramine and attributed the persistent germicidal activity of hypochlorites in sewage to the formation of chloramine and chloramine derivatives. Further evidence against the nascent oxygen theory of chlorine disinfection is to be found in the fact that such active oxidising agents as sodium, potassium, and hydrogen peroxides have a much lower germicidal activity than chlorine when compared on the basis of their oxygen equivalents. Table III shows chlorine to be approximately five times as active as potassium permanganate when compared on this basis. TABLE III.[A]--COMPARISON OF BLEACH AND POTASSIUM PERMANGANATE -----------+------------------+------------------- | BLEACH | |Available Chlorine| POTASSIUM Contact | 0.35 p.p.m. | PERMANGANATE. Period. +------------------+------------------- |Oxygen Equivalent. Parts Per Million. +--------+---------+---------+--------- | 0.08 | 0.133 | 0.266 | 0.400 -----------+--------+---------+---------+--------- Nil | 140 | ... | ... | ... 30 mins | 90 | 122 | 115 | 110 1 hour | 68 | 115 | 100 | 80 1-1/2 hours| 63 | 108 | 95 | 75 4 hours | 50 | 95 | 80 | 50 -----------+--------+---------+---------+--------- [A] Results are _B. coli_ per 10 c.cms. The germicidal activity of oxidising agents has been shown by Novey and others to be somewhat proportional to the energy liberated during the reaction but even when this factor is taken into consideration chlorine compounds are more active than other oxidising agents. Hypochlorous acid is far superior to hydrogen peroxide as a germicidal agent and is as active as ozone, which liberates a greater amount of energy. 2HClO = 2HCl + O_{2} + 18,770 calories 2H_{2}O_{2} = 2H_{2}O + O_{2} + 46,120 calories 2O_{3} = 3O_{2} + 60,000 calories.