Viii INTEODUCTORY NOTE. 



At this point Lister came forward with a scientific 

 principle which rendered all plain. Dirt was fatal, not 

 as dirt, but because it contained living germs which, 

 as Schwann was the first to prove, are the cause of 

 putrefaction. Lister extended the generalization of 

 Schwann from dead matter to living matter, and by 

 this apparently simple step revolutionized the art of 

 surgery. He changed it, in fact, from an art into a 

 science. 



' Listerism ' is sometimes spoken of as if it merely 

 consisted in the application of carbolic acid spray; 

 but no man of any breadth of vision will regard the 

 subject thus. The antiseptic system had been enun- 

 ciated, expounded, and illustrated, prior to the intro- 

 duction of the spray. The spray is a mere offshoot of 

 the system — elegant and effective it is true, but still 

 a matter of detail. In company with my excellent 

 friend Mr. John Simon, I once visited St. Bar- 

 tholomew's Hospital, and became acquainted, in its 

 wards, with the practice of the late Mr. Callender. 

 The antiseptic system was there as stringently applied 

 as at King's College. Immediately before his departure 

 to America I spoke to Mr. Callender on this subject ; 

 and he then told me expressly, that his aim and hope 

 had been, not to introduce a new principle, but to 

 simplify the methods of Lister. And yet Mr. Callen- 

 der's practice is sometimes spoken of as if it were, in 

 principle, different from that of his eminent contem- 

 porary. 



It is interesting, and indeed pathetic, to observe 

 how long a discovery of priceless value to humanity 



