356 AN ADDRESS ON 



I have referred to, you would find that complete primary union, instead of being 

 a rarity as formerly, would be a matter of very frequent occurrence ; although 

 3^ou would not be at all able to reckon upon the constancy of aseptic results 

 which may be obtained by the right use of chemical antiseptics. 



Iodoform is an agent very much trusted by some surgeons. It is a very 

 peculiar antiseptic, having extremely little influence over the growth of bacteria 

 outside the body. That was illustrated by a very simple experiment I performed 

 a good many years ago. I took two purified stoppered bottles, and put into one 

 of them cotton-wool strongly impregnated with iodoform — lo per cent, iodoform 

 wool ; and into the other ordinary absorbent wool. I poured milk from a dairy 

 into each, just sufficient to soak the mass of cotton, and left them at the tem- 

 perature of the air. In one of these bottles the milk was thus most intimately 

 associated with iodoform, yet it soured like that in the other bottle, though 

 somewhat later, and when I examined a little of the iodoform wool under the 

 microscope, I found the milk which it contained teeming with bacteria of different 

 species. That simple experiment was enough to show how little power iodoform 

 exerts over the growth of microbes outside the body. This conclusion has 

 since been amply confirmed by the observations of others. It has been even 

 ascertained, as a matter of experiment, that if iodoform is dusted over sterilized 

 cultivating jelly in a test-tube, growth will take place from organisms that were 

 contained in the iodoform itself. 



But though such is the case, it is nevertheless unquestionably true that 

 iodoform exercises a powerful antiseptic influence upon wounds. The most 

 probable explanation of this apparent anomaly is that suggested by Behring, 

 namely, that iodoform produces its beneficial effects, not by acting directly upon 

 the bacteria, but by inducing chemical changes in their toxic products. Behring 

 has ascertained as a matter of fact that some of these toxines are altered chem- 

 ically by iodoform and at the same time rendered harmless. Two of his experi- 

 ments, performed in conjunction with De Ruyter, may be quoted in illustration. 

 A ptomaine obtained from a culture of pyogenic micrococci killed a mouse in 

 twelve hours when injected pure into the peritoneal cavity, but proved entirely 

 harmless under similar circumstances when mixed with a little iodoform. Again, 

 a sample of decomposing pus, which had fatal effects when introduced unmixed 

 into the peritoneum of the mouse, had no influence whatever upon the health 

 of the animal if treated with iodoform, which meanwhile left intact the pyogenic 

 microbes.^ In the absence of their toxic products, the bacteria could do little 

 harm, and would probably soon be disposed of by phagocytosis. 



* See De Ruyter, ' Zur lodoformfrage,' Langenbeck's Archiv, 1887, p. 984. Some bacteria are more 

 affected than others by the direct action of iodoform. In the special case of the cholera microbe it seems 

 to act as a poison. See Neisser, Centralblatt fi'iv Bacteriologie, 1888, p. 387. 



