234 Messrs. Dakin, Cohen, Daufresne, and Kenyon. 



from the Table of Kesults (p. 243), possess powerful germicidal properties. It is 

 worthy of note that, as shown in the case of the derivatives of acylanilides, 

 marked germicidal properties only appear on the introduction of chlorine 

 attached to nitrogen. The parent substances from which these chloramines 

 are prepared, whether unsubstituted or containing chlorine attached to carbon, 

 show no such action. 



The bacteriological tests were made by determining the approximate 

 concentration necessary to sterilise completely one or two drops of a 24-hour- 

 old culture of a vigorous strain of Staphylococcus aureus in a total volume of 

 5 c.c. In a number of cases other suitable organisms, especially pyocyaneus, 

 were used as well. Two sets of tests were made, one in which the organisms 

 were suspended in water, the other in which the fluid contained 50 per cent, 

 of horse serum, as it is well known that the presence of serum or other proteins 

 markedly inhibits the action of all known antiseptics. The practical details 

 are noted later. 



The substances tested include the following groups : — 

 Series I. — Chloramine compounds in which the NCI group is separated 

 from a benzene nucleus by the SC^Na group. 

 „ II. — Naphthalene derivatives similar to the above. 



III. — Other dicyclic derivatives of similar type. 

 „ IV. — Chloramines in which the NCI group is directly attached to 



a benzene nucleus. 

 „ V. — Bromamines. 



„ VI. — Products of the action of hypochlorite on proteins, etc. 

 „ VII. — Certain other compounds for comparison. 



A superficial consideration of the results contained in the above Table at 

 once permits certain simple deductions : — 



(1) Almost all of the substances examined containing the (NCI) group 

 possess very strong germicidal action. 



(2) The presence in the molecule of more than one (NCI) group does not 

 confer any marked increase in germicidal power ; compare substances 20, 24, 

 25, and 26. 



(3) The germicidal action of many of these chloramine compounds is 

 molecule for molecule greater than that of sodium hypochlorite.* Thus 

 p-toluene sodium sulphochloramide with a molecular weight for the crystal- 

 lised salt of 261"5 is as active as sodium hypochlorite with a molecular 

 weight of 74. 



* Rideal (' Journ. Roy. San. Inst.,' vol. 31, p. 33, 1910) had shown previously that 

 addition of ammonia to hypochlorite with formation of NH 2 C1 can lead to an increase 

 over the original germicidal action of the original hypochlorite. 



