PREFACE. 



THE Author, in yielding to the wish convoyed to him to repub- 

 lish, in their present form, the two accompanying Lectures, does 

 so, in the hope, that the attainment of the object contemplated 

 by them will thereby bo furthered, 



The first Lecture, delivered under the title of " Proventiblo 

 Diseases," gave, the Author believes, the first expression, to 

 a popular audience, of the " Germ Theory " of Zymotic 

 Disease. 



It is to the indomitable genius and philosophical sagacity 

 of Joseph Lister that, the contest, in regard to the application 

 of this theory to Surgery, is now virtually ended ; and, thereby, 

 one of the brightest, most benign, and even romantic chapters 

 has boon added to the history of Medical Hurgory. 



The battle of the germ theory, however, in its relation to 

 the State control and prevention of infectious diseases, hat 

 yet largely to be fought; and, to assist forward this great 

 niov<;m<!iil, iti liowcvor siii.-ill ;i <lrrn',<i, is tin; objwl in iv.pul) 

 lishing this Lecture. 



The second Lecture sufficiently explains its aim. It is 

 intended to direct public attention to the great, and, as the 

 Author thinks, preventiblo waste of life, incurred by a large 

 section of workmen among the industrial class, in the pursu it 

 of their employments. The appended tablet exhibit the eft ects, 



