DUST AND DISEASE. 25 



organism to be detected in the putrefying pus? Yes, gentle- 

 men, there is. If any drop of the putrid matter is examined 

 with a good glass, it is found to be teeming with myriads of 

 minute jointed bodies, called vibrios, which indubitably pro- 

 claim their vitality by the energy of their movements. It 

 is not an affair of probability, but a fact, that the entire 

 mass of that quart of pus has become peopled with living 

 organisms as the result of the introduction of the canula and 

 trocar ; for the matter first let out was as free from vibrios 

 as it was from putrefaction. If this be so, the greatness of 

 the chemical changes that have taken place in the pus ceases 

 to be surprising. We know that it is one of the chief pecu- 

 liarities of living structures that they possess extraordinary 

 powers of effecting chemical changes in materials in their 

 vicinity, out of all proportion to their energy as mere chemical 

 compounds. And we can hardly doubt that the animalcules 

 which have been developed in the albuminous liquid, and 

 have grown at its expense, must have altered its constitu- 

 tion, just as we ourselves alter that of the materials on which 

 we feed.^ 



In antiseptic operations care is taken that every 

 portion of tissue laid bare by the knife shall be de- 

 fended from germs; that if they fall upon the wound 

 they should be killed as they fall. With this in 

 view he showers upon his exposed surfaces the spray of 

 dilute carbolic acid, which is particularly deadly to the 

 germs, and he surrounds the wound in the most careful 

 manner with antiseptic bandages. To those accustomed 

 to strict experiment it is manifest that we have a strict 

 experimenter here — a man with a perfectly distinct 

 object in view, which he pursues with never-tiring 

 patience and unwavering faith. And the result, in his 

 hospital practice, as described by himself, has been, 

 that even in the midst of abominations too shocking 

 to be mentioned here, and in the neighbourhood of 



' Introductory Lecture before the University of Edinburgh. 



