AND THE HEALING ART 499 



that carbolic acid, b\- virtue of its powerful affinity for the epidermis and oily 

 matters associated with it, and also its great penetrating power, is still the best 

 agent at our disposal for purifying the skin around the wound. But I must 

 say a few words regarding a most important simplification of our procedure. 

 Pasteur, as we have seen, had shown that the air of every inhabited room teems 

 with microbes ; and for a long time I employed various more or less elaborate 

 precautions against the living atmospheric dust, not doubting that, as all wounds 

 except the few wliich healed completely by the first intention, underwent 

 putrefactive fermentation, the blood must be a peculiarly favourable soil for 

 the growth of putrefactive microbes. But I afterwards learnt that such was 

 by no means the case. 1 had performed many experiments in confirmation 

 of Pasteur's germ theory, not indeed in order to satisfy myself of its truth, 

 but in the hope of convincing others. I had observed that uncontaminated 

 milk, which would remain unaltered for an indefinite time if protected from 

 dust, was made to teem with microbes of different kinds by a very brief exposure 

 to the atmosphere, and that the same effect was produced b\- tlie addition of 

 a drop of ordinary water. But when I came to experiment with blood drawn 

 with antiseptic precautions into sterilized vessels, I saw to my surprise that 

 it might remain free from microbes in spite of similar access of air or treatment 

 with water. I even found that if very putrid blood was largely diluted with 

 sterilized water, so as to diffuse its microbes widely and wash them of their 

 acrid products, a drop of such dilution added to pure blood might leave it 

 unchanged for days at the temperature of the body, although a trace of tlie 

 septic liquid undiluted caused intense putrefaction within twenty-four hours. 

 Hence I was led to conclude that it was the grosser forms of septic mischief, 

 rather than microbes in the attenuated condition in which they existed in the 

 atmosphere, that we had to dread in surgical practice. And at the London 

 Medical Congress in 1881, I hinted, when describing the experiments I have 

 alluded to, that it might turn out possible to disregard altogether the atmo- 

 spheric dust. But greatly as I should have rejoiced at such a simplification of 

 our procedure, if justifiable, I did not then venture to test it in practice. I knew 

 that with the safeguards which we then employed I could ensure the safety 

 of my patients, and I did not dare to imperil it by relaxing them. Tliere 

 is one golden rule for all experiments upon our fellow men. Let the thing 

 tried be that which, according to our best judgement, is the most likely to 

 ]:)romote the welfare of the patient. In other words. Do as you would be 

 done by. 



Nine years later, however, at the Berlin Congress in iSqo, I was able to bring 

 forward what was, 'I believe, absolute demonstration of the harmlessness of 



