AN ADDRESS ON A NEW ANTISEPTIC DRESSING 311 



whipping the blood of the ox so as to get rid of the fibrine, proved equivalent 

 antiseptically to bichloride of mercury. 



I may perhaps say in a few words how the experiments were conducted. 

 For the purpose of ascertaining whether a given antiseptic can or cannot prevent 

 development of organisms, a very simple mode of experimentation suffices. 

 What we have to do is to ascertain whether it is inhibitory, not whether it is 

 germicidal. The only special apparatus required for such experiments is a warm 

 chamber which can be kept pretty constantly about the temperature of the 

 human blood. Beyond this a few stoppered bottles, with well-fitting stoppers — 

 perhaps half-ounce stoppered bottles — are really all that is required. Into 

 a series of such bottles serum of the blood, to the amount, say, of 150 grains, 

 containing solutions of the antiseptic of different strengths, is introduced. 

 These are all inoculated by means of a small syringe pipette with the same 

 quantity, say, i-ioth of a minim, of some potently septic liquid, such as blood- 

 serum in a state of advancing putrefaction. The bottles are placed in the 

 incubator, and then, if development takes place, that is evidence that in the 

 bottle in which it occurs such proportion of the antiseptic as that bottle contains 

 is inadequate ; if no development occurs, we have proof of antiseptic efficacy. 

 The transparency of the serum permits a recognition of the development of the 

 organisms, which invariably causes opacity. If we have no change in this 

 respect, if the serum maintains its transparency, at the same time keeping its 

 odour unimpaired, and, further, if microscopic examination of any little sediment 

 there may be shows that it contains no organisms, we have clear evidence that 

 the antiseptic in the proportion concerned has proved efficacious. 



Now if the sal alembroth was equivalent to the bichloride of mercury, 

 weight for weight, that shows that the sal alembroth was realh' more efficacious 

 as regards the quantity of bichloride of mercury- it contained. The bichloride 

 of mercury having the sal alembroth added to it, and also water in the double 

 salt that is formed, is increased in atomic weight very considerably ; and there- 

 fore if an equal weight of alembroth is equivalent in antiseptic action to bichloride 

 of mercury, that shows that the bichloride of mercury is made more efficacious 

 in the blood-serum by the addition of the chloride of ammonium. The chloride 

 of ammonium in combination protects the bichloride of mercury, so to speak, 

 to a certain extent, from the interfering influence of the albumen. 



At the same time, the sal alembroth proved much less irritating than 

 bichloride of mercury. Experimenting on mv own skin, I ascertained that it 

 has certainly not half the irritating property of corrosive sublimate. The 

 chloride of ammonium attached to the bichloride of mercury, while it protects 

 the bichloride in some degree from the influence of albumen interfering with 



