300 FRAGMENTS OF SCIENCE. 



and who are most ready to admit, as regards even higher 

 things than this, the potentialities of matter, will be the 

 Jast to accept these rash hypotheses. 



The Germ-Theory applied to Surgery. 



Not only medical but surgical science is now seeking 

 light and guidance from this germ-theory. Upon it the 

 antiseptic system of Professor Lister, of Edinburgh, is 

 founded ; and if the facts be correctly given, the results 

 are extraordinary. As already stated, the germ-theory of 

 putrefaction was started by Schwann, but the illustrations 

 of this theory adduced by Professor Lister are of such, pub- 

 lic moment as not only to justify, but to render imperative, 

 their introduction here : 



Schwann's observations, says Professor Lister, did not receive the 

 attention which they appear to me to have deserved. The fermentation 

 of sugar was generally allowed to be occasioned by the torula cerevisice ; 

 but it was not admitted that putrefaction was due to an analogous 

 agency. And yet the two cases present a very striking parallel. In 

 each a stable chemical compound, sugar in the one case, albumen in the 

 other, undergoes extraordinary chemical changes under the influence of 

 an excessively minute quantity of a substance which, regarded chemi- 

 cally, we should suppose inert. As an example of this in the case of 

 putrefaction, let us take a circumstance often witnessed in the treatment 

 of large chronic abscesses. In order to guard against the access of at- 

 mospheric air, we used to draw off the matter by means of a canula and 

 trocar, such as you see here, consisting of a silver tube with a sharp- 

 pointed steel rod fitted into it, and projecting beyond it. The instru- 

 ment, dipped in oil, was thrust into the cavity of the abscess, the trocar 

 was withdrawn, and the pus flowed out through the canula, care being 

 taken by gentle pressure over the part to prevent the possibility of 

 regurgitation. The canula was then drawn out with due precaution 

 against the reflux of air. This method was frequently successful as to 

 its immediate object, the patient being relieved from the mass of the ac- 

 cumulated fluid, and experiencing no inconvenience from the operation. 

 But the pus was pretty certain to reaccumulate in course of time, and it 

 became necessary again and again to repeat the process. And unhappily 



