THE ANTISEPTIC MANAGEMENT OF WOUNDS 359 



gauze had upon the bichloride. The combination with zinc keeps the cyanide 

 of mercury from being dissolved away, and also prevents it from irritating. 

 It is, so to speak, chained down by the cyanide of zinc with which it is combined. 

 The double salt is very little soluble in blood-serum, requiring between two and 

 three thousand parts to dissolve it ; and thus a small quantity of it will last 

 a long time in spite of a free flow of discharge through it. It thus fulfils the 

 condition of persistent storage. It is at the same time practically unirritating ; 

 wounds heal under its immediate contact without the necessity for a protective 

 layer interposed. Then, as to the essential question of its antiseptic virtues. 

 Small as is the quantity which serum dissolves, it proves amply sufficient to 

 prevent bacteric development. Thus in one experiment some serum of horse's 

 blood containing i-5,oooth part of the salt remained clear and odourless for more 

 than a fortnight at the temperature of the body in spite of inoculation with 

 putrid material, and even i-io,oooth part prevented all growth for ten days. 

 When mixed with serum and corpuscles, it prevents putrefaction in smaller 

 quantity than any other antiseptic with which I am acquainted. The greater 

 the amount of albuminoid substances in any solution, the more severeh' is the 

 antiseptic tested ; and when the red corpuscles are mingled with the serum, as is 

 the case in the first twenty-four hours after the infliction of a wound, a much 

 larger amount of the antiseptic is needed than with serum only. Thus four times 

 as much corrosive sublimate is required to prevent putrefaction in serum and 

 corpuscles as in serum. Now, the double cyanide answers the purpose in half 

 the quantity that is necessary with corrosive sublimate. As an illustration of the 

 practical value of this material, I may mention a single experiment, not hitherto 

 published. I packed a piece of glass tube with gauze charged with 3 per cent. 

 ' of the double salt, and poured into it serum and corpuscles obtained by whipping 

 pig's blood. I then inoculated one end of the saturated gauze with a drop of 

 septic serum, and kept it at the temperature of the body, with provision for 

 preventing evaporation. After the lapse of five days I found the entire mass 

 of gauze pure in odour and without bacteric development, as tested by micro- 

 scopic examination of stained cover-glass preparations of the contained blood. 

 Meanwhile a piece of unprepared gauze similarl}/ treated showed bacteric 

 development within twenty-four hours. 



But here I must remind you of the essential difference, wliich must always 

 be kept in view in considering antiseptic agents, between germicidal and inhibitory 

 power ; that is to say, between the capabilit}- of destroying the life of microbes 

 and that of preventing their growth while the agent remains in contact witli 

 them. These two properties are by no means similarly jMoportioncd to 

 each other in all antiseptics. Thus, cyanide of mercury is far sujK'rior to the 



