302 FRAGMENTS OF SCIENCE. 



tides of dust will be pretty sure to contain the germs of putrefactive 

 organisms, and if one such is left in the albuminous liquid, it will 

 rapidly develop at the high temperature of the body, and account for 

 all the phenomena. 



But striking as is the parallel between putrefaction in this instance 

 and the vinous fermentation, as regards the greatness of the eftbrt pro- 

 duced, compared with the minuteness and the inertness, chemically 

 speaking, of the cause, you will naturally desire further evidence of the 

 similarity of the two processes. You can see with the microscope the 

 torula of fermenting must or beer. Is there, you may ask, any organism 

 to be detected in the putrefying pus? Yes, gentlemen, 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 proclaim 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 peculiari- 

 ties of living structures that they possess extraordinary powers of effect- 

 ing 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 constitution, just 

 as we ourselves alter that of the materials on which we feed. 1 



Secured from the clanger of putrefaction, it is amazing 

 how, under the hands of a really able surgeon, the human 

 flesh and bones may be cut, torn, and crunched with im- 

 punity. The accounts of the operations of our eminent 

 surgeons read like romance. On this, however, I must not 

 dwell further than to recommend to your attention a case 

 described in the British Medical Journal for the 14th of 

 January last. In the operations of Professor Lister care 

 is taken that every portion of tissue laid bare by the knife 

 shall be defended from germs ; that if they fall upon the 

 wound the}' shall be killed as they fall. With this in view 



1 Introductory Lecture before the University of Edinburgh. 



