170 ANTISEPTICS 



the real causes of a material being an antiseptic are very- 

 obscure, and at present we can only have a remote idea of the 

 factors at work. 



The Effects of certain Antiseptics. — Here we can only 

 briefly indicate certain results obtained with the more common 

 members of the group. 



Chlorine. — All the halogens have been found to be powerful 

 antiseptics, but from the cheapness with which it can be produced 

 chlorine has been most used ; it is the chief active agent in the somewhat 

 complex action of bleaching powder. Nissen, investigating the action of 

 the latter, found that ~i.\ per cent, killed typhoid bacilli in feces ; and 

 Rideal found that 1 part to 400-500 disinfected' sewage in fourteen 

 minutes, and Delepine's results show that 1 part to 50 (equal to - 66 per 

 cent, of chlorine) rapidly kills the tubercle bacillus, and 1 part to 10 

 (equal to 3 '3 per cent.) killed anthrax spores. Klein found that '05 per 

 cent, of chlorine killed most bacterial spores in five minutes. 



Hypochlorous Acid and Hypochlorites. — These enter into the action of 

 bleaching powder, and their potency as antiseptics has been long known. 

 Recently they have been much used in connection with war-surgery. The 

 chief preparations are the following : (1) Eusol (Lorrain Smith). This 

 is made by dissolving 12 '5 gr. good bleaching powder and 12 "5 gr. boric 

 acid in one litre of water, shaking up from time to time for two hours and 

 filtering ; this solution, while containing abundant free hypochlorous acid 

 (about 0'26 per cent.), has, in consequence of the formation of calcium 

 biborate, a low free hydrogen-ion concentration — it thus cannot become 

 definitely acid and is relatively non-irritant to the tissues. (2) Dakin- 

 Daufresne solution. 20 gr. average bleaching powder is shaken up in 

 half a litre of water and left for six to twelve hours ; 10 gr. dry sodium 

 carbonate and 8 gr. sodium bicarbonate are dissolved in another half-litre 

 of water and added to the bleaching powder solution ; the mixture is well 

 shaken, allowed to stand for half an hour, and the liquid is siphoned off 

 and filtered through double filter paper. This solution contains 0'45 

 per cent, sodium hypochlorite and is alkaline. 



Iodine is a powerful antiseptic and as Tr. Iodi is of great use in purify- 

 ing the skin before surgical incision. 



Iodine Terchloride. — This is a very unstable compound of iodine and 

 chlorine, and, seeing that the substance only remains as IC1 3 in an 

 atmosphere of chlorine gas, it is open to doubt whether the antiseptic 

 effects attributed to it are not due to a very complicated action of free 

 hydrochloric acid, hydriodic acid, of oxyacids of chlorine and iodine 

 produced by its decomposition, and also, in certain cases, of organic 

 iodine compounds formed from its contact with albuminous material. 

 It is stated that the action is very potent : a 1 per cent, solution is said 

 instantly to kill even anthrax spores, but if the spores be in bouillon, 

 death occurs after from ten to twelve minutes. In serum the necessary 

 exposure is from thirty to forty minutes. A solution of 1-1000 will kill 

 the typhoid, cholera, and diphtheria organisms in five minutes. 



If ascent Oxygen. — This is chiefly available in two ways — firstly, when 

 in the breaking up of ozone the free third atom of the ozone molecule is 

 seeking to unite with another similar atom ; secondly,- when peroxide of 

 hydrogen is broken up into water and an oxygen atom is thereby liberated. 

 In commerce the activity of " Sanitas " compounds is due to the formation 



