PREFACE 



TO THE SECOND EDITION. 



THE views concerning the nature and origin of disease 

 germs,' now published for the first time in a connected 

 form, were briefly sketched in the lectures I delivered 

 at Oxford in 1868-9 by direction of the Radclifife 

 Trustees, and have been taught by me in my lectures 

 at King's College for many years past. The con- 

 clusions arrived at have resulted from careful micro- 

 scopic investigation, of the tissues and fluids of the 

 body carried out by the aid of the highest magnifying 

 powers yet made. Some of the facts will be found 

 recorded in my Report on the Cattle Plague in 1866, 

 arid in memoirs and works published as early as 1863. 

 The treatment of febrile diseases discussed in the 

 latter part of this volume formed the subject of 



