376 LAY SERMONS, ADDRESSES, AND REVIEWS. [xv 



Tliere can be no reason, then, for donbting that, 

 among insects, contagious and infectious diseases of 

 great malignity are caused by minute organisms which 

 are produced from pre-existing germs, or by homogene- 

 sis ; and there is no reason, that I know of, for believ- 

 ing that what happens in insects may not take place 

 in the highest animals. Indeed, there is already strong 

 evidence that some diseases of an extremely malignant 

 and fatal character, to which man is subject, are as 

 much the work of minute organisms as is the Pebrine. 

 I refer for this evidence to the very striking facts ad- 

 duced by Professor Lister in his various well-known 

 publications on the antiseptic method of treatment. 

 It seems to me impossible to rise from the perusal of 

 those publications without a strong conviction that 

 the lamentable mortality which so frequently dogs the 

 footsteps of the most skilful operator, and those deadly 

 consequences of wounds and injuries which seem to 

 haunt the very walls of great hospitals, and are, even 

 now, destroying more men than die of bullet or bayo- 

 net, are due to the importation of minute organisms 

 into wounds, and their increase and multiplication; 

 and that the surgeon who saves most lives will be he 

 who best works out the practical cou sequences of the 

 hypothesis of Redi. 



I commenced this Address by asking you to follow 

 me in an attempt to trace the path which has been fol- 

 lowed by a scientific idea, in its long and slow pro- 

 gress from the position of a probable hypothesis to that 

 of an established law of Nature. Our survey has not 

 taken us into very attractive regions; it has lain, 

 chiefly, in a land flowing with the abominable, and 

 peopled with mere grubs and mouldiness. And it may 

 be imagined with what smiles and shrugs practical 

 and serious contemporaries of Ecdi and of Spallanzam 



