358 AN ADDRESS ON 



defilement, must require an almost impossible degree of care in its manipulation. 

 I have seen this system in operation in very able hands with results by no 

 means satisfactory. 



An external antiseptic dressing, to be ideally perfect, should have four 

 essential qualities. It should contain some thoroughly trustworthy antiseptic 

 ingredient ; it should have that substance so stored up that it cannot be dissipated 

 to a dangerous degree before the dressing is changed ; it should be entirely 

 unirritating ; and it should be capable of freely absorbing any blood and serum 

 that may ooze from the wound. 



The carbolic gauze which we formerly used did, indeed, contain a very 

 efficient antiseptic ; but this, being volatile, was perpetually flying off in spite 

 of our endeavours to fix it, and it was a matter of uncertainty in how many days 

 it might have so far disappeared from the dressing as to leave it untrustworthy. 

 Carbolic acid had also this disadvantage as an element of an external dressing 

 that, acting, as we have seen, with peculiar energy on the epidermis, it interfered 

 seriously with cicatrization, and we were obliged to interpose what we termed 

 a ' protective ' to shield the healing wound from its action. And this gauze, con- 

 taining resin for the purpose of fixing the carbolic acid, was not a very good 

 absorber of blood and serum. Carbolic gauze, then, was not an ideally perfect 

 dressing. 



Corrosive sublimate had the advantage over carbolic acid of not being 

 volatile. But it was readily washed out of gauze or wool charged with it, and 

 under some circumstances it proved very irritating. The discharge, passing 

 from one part of the dressing to another, took up more and more of the bichloride 

 in its passage, and sometimes became so strong a solution of the salt as to cause 

 vesication. I endeavoured to remedy these defects by combining the bichloride 

 with the albumen of the serum of horse's blood. ^ But though the sero-sublimate 

 gauze answered its purpose, in so far that it contained the bichloride better stored 

 up and in a less irritating form, it had inconveniences, especially as regards its 

 preparation, which induced me to abandon it. 



The agent which we have found the most satisfactory as the antiseptic 

 ingredient of the dressing is the double cyanide of mercury and zinc.^ Cyanide 

 of mercury, while it has pow^erful antiseptic properties, is very soluble and highly 

 irritating ; but the combination of cyanide of zinc with it has the same sort 

 of effect, but in a much higher degree, as the albumen of the sero-sublimate 



^ British Medical Journal, October 25, 1884 (p. 301 of this volume). 



^ This is a double salt of a very peculiar constitution. It has been specially investigated by Professor 

 Dunstan, who concludes that it has the following formula : 4ZnCy._i, HgCyj. See Trans. Chem. Soc, 

 1892, p. 666. The best way of preparing it was described by Professor Dunstan in the Pharmaceutical 

 Journal, third series, vol. xx, No. 653. 



^ If 



