136 



Bactericidal Pi^operties Conferred on the Blood by Intravenous 

 Injections of Diamirio-Acridine Sulphate.''^ 

 By C. H. Browning and E. Gulbransen. 



(Communicated by Prof. E. Muir, F.E.S. Eeceived August 11, 1917.) 



(Fiom the Bland-Sutton Institute of Pathology, Middlesex Hospital.) 



Attempts to achieve "internal disinfection," that is to say, to kill 

 organisms in the body of infected animals by means of dri;gs, have hitherto 

 afforded little promise of success in the case of tlie common pathogenic 

 bacteria, the only exception being the action of ethyl-hydrocuprein in 

 pneumococcus infectious, discovered by Morgenroth with his co-workers, 

 Levy and others. The reasons for the failure are probably to be attributed 

 mainly to two facts; in the first place, antiseptics in general enter into 

 combination with proteins of the tissues and body fluids, either by a process 

 of physical adsorption or by the formation of chemical compounds. In either 

 case, the usual result is that the l^actericidal action of a substance, as 

 determined in a watery medium, is greatly reduced by protein-solutions, e.(/., 

 serum. Secondly, the majority of chemical antiseptics are general protoplasm 

 poisons, and exert on mammalian tissues a degree of toxic action equal to, 

 or greater than, that which they exhibit towards micro-organisms ; hence 

 these substances prove lethal for animals in doses wliich are insufficient to 

 confer bactericidal properties on the body fluids. 



The classical example of such failures was afforded b}' mercuric chloride, 

 which Koch employed in the hope of treating effectively antlirax septicaemia 

 in animals. Ehrlich and Bechhold investigated compounds which were more 

 potent antiseptics than any liitherto known, among the most active being 

 tetrabrom- (and chlor-) ortho-biphenol ; they found, however, that the 

 bactericidal properties of these substances were also greatly reduced when 

 the organisms were suspended in a serum medium. Thus, tetrachlor-ortho- 

 biphenol in a concentration of 1 : 320,000 prevented the growth of diphtheria 

 bacilli in boiiillon, whereas in serum growth occurred in the presence of 

 1 : 10,000 of this reagent. Similarly we have found that the dose of per- 

 chloride of mercury which is required to inhibit completely the growth of 

 Staphylococcus aureus or B. coli in serum is 100 times greater than that 

 which jDroduces this effect in watery medium containing a small amount 

 of nutrient peptone (0-7 per cent.). 



* We are indebted to th« Medical Eeseaich Committee for a grant towards the 

 expenses of this work. 



