Antiseptic Action of Substances of the Chloramine Group. 233 



about in some of the compounds of the living cell, either by direct action of 

 the antiseptic or by the action of products formed from the antiseptic by 

 combination with substances present in the medium in which the organisms 

 are suspended. Among the chemical substances present in living cells 

 capable of reacting with hypochlorites, the proteins appear likely to play a 

 dominant rale. Under conditions of practical use antiseptics commonly act 

 upon organisms suspended in a medium more or less rich in proteins. 

 Hence hypochlorites might be expected to react on both intra- and extra- 

 cellular proteins. 



The action of hypochlorites upon proteins consists, at least in part, in the 

 replacement of the hydrogen of some of the (NH) groups by chlorine, thus 

 forming substances of the chloramine group.* The reaction is somewhat 

 complicated by other changes which will be referred to in more detail later. 

 Now the ability of hypochlorites to attack proteins with the formation of 

 substances containing halogen directly linked to nitrogen appears to be 

 related to their bactericidal action. One piece of indirect evidence may be 

 quoted at once. Free chlorine, bromine, and iodine have not widely differing 

 germicidal power, but when the halogen is converted into hypochlorite or 

 hypobromite, a very marked difference appears. The germicidal action of the 

 hypochlorites, when tested against staphylococci suspended in water, is of a 

 similar order to that of free chlorine, that of hypobromite is only about 

 1 per cent, of that of free bromine, while a solution of iodine in weak alkali, 

 which may contain unstable hypo-iodite, has a negligible germicidal 

 activity. This feeble germicidal action of hypobromite and hypo-iodite may 

 well be related to their known sluggishness in reacting with proteins and 

 amino-acids compared with the comparative activity of the hypochlorites.f 

 The probability that the formation from proteins of substances containing 

 halogen linked to nitrogen was an intermediate agent in the germicidal action 

 of hypochlorites made it desirable to make a systematic investigation of the 

 germicidal properties of a large number of substances of varied type 

 containing the same (NCI) group. Most of these substances, as will be seen 



* Hopkins and Pinkus ('Ber.,' vol. 31, p. 1311, 1898) showed that proteins which had 

 been treated with a large excess of chlorine contained part of the lialogen in a loosely 

 combined form capable of liberating iodine from potassium iodide. The view that these 

 substances contained chlorine attached to nitrogen was first put forward by Cross, Bevan, 

 and Briggs (' Journ. Soc. Chem. Ind.,' vol. 27, p. 260, 1908). In a previous communica- 

 tion by one of us (H. D. D.) this paper was unfortunately overlooked. 



t Compare Struhetz ('Monatsh.,' vol. 27, p. 601, 1906). Langheld ('Ber.,' vol. 42, 

 p. 2360, 1909) states that gelatine is not attacked by cold sodium hypochlorite. This 

 erroneous conclusion is apparently based on the observation that on mixing the two 

 solutions, unchanged hypochlorite persists, but as a matter of fact the bulk of the 

 hypochlorite readily reacts with the gelatine. 



VOL. LXXX1X. — B. U 



