278 AN ADDRESS ON THE TREATMENT OF WOUNDS 



assumed that ordinary water contained putrefactive bacteria in a form that 

 would develop in serum. 



But when in the course of an experiment to be again referred to, I drew 

 blood, with antiseptic precautions, from the jugular vein of an ox into a series 

 of purified bottles, about half an ounce into each, and, having allowed the blood 

 to coagulate and the clot to shrink, introduced various quantities of tap water 

 to mingle with the expressed serum in the several vessels, I found, to my surprise, 

 that not only an entire minim, but two, four, and even eight minims, failed to 

 induce putrefaction, although the bottles were kept in a warm box at the 

 temperature of the body. I have since confirmed this experiment in the ox, 

 and have also extended it to the blood of other animals — the donkey and the 

 dog — with similar results. I even found that putrid blood in full activity, if 

 largely diluted with water purified by boiling, and introduced in small quantity 

 in proportion to the serum, failed to occasion putrefaction or the development 

 of any organisms that I could discover by ordinary microscopic examination. 

 Yet the same quantities of the same dilutions quickly gave rise to putrefaction 

 in blood of the same animal altered by mixing it with an equal part of purified 

 water, showing that they really possessed septic energy, though unable to exert 

 it upon normal serum. Not that the blood of these animals was in its natural 

 state incapable of putrefaction, for inoculation with a very small quantity of 

 undiluted putrid blood soon rendered it highly offensive. But the results of these 

 experiments seemed to point to the remarkable conclusion that, after having 

 been widely diffused by means of water, bacteria are incapable of developing in 

 undiluted healthy serum. In this respect serum is totally different in its be- 

 haviour from milk, in which, as I have shown elsewhere,^ a single Bacterium 

 ladis, detached from others by a similar process of diffusion by means of water, is 

 as sure to produce its kind as are a million taken directly from souring milk. 



How it is that the diffusion of bacteria renders them incapable of developing 

 in serum I do not profess to understand. It may perhaps be that when bacteria 

 are introduced directly from putrid blood, the products of the putrid fermen- 

 tation adhering to them may induce chemically an alteration in the normal 

 qualit}^ of the serum which, when thus impaired, may prove amenable to the 

 nutritive energies of the micro-organisms, while conversely copious ablution 

 with water may remove from the bacteria the associated substances which 

 thus act as their pioneers. This view might be otherwise expressed by saying 

 that the bacteria per se are unable to grow in normal serum, and can only 

 develop in that liquid when it has been vitiated, whether by the addition of 

 water or by the action of small quantities of the acrid products of putrefaction. 



* Vide Path. Trans., loc. cit. (see vol. i, p. ^ys)- 



