Of THE 



UNIVERSITY 



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PREFACE TO THE THIRD EDITION, 



THE call for a third edition of this book, coming so 

 soon after the appearance of the second edition, is a 

 source of no small degree of gratification to the author. 



During the interval of about twelve months that has 

 elapsed since the appearance of the second edition ad- 

 vances have been made along the manifold lines of 

 bacteriological research, but they have not been of a 

 nature to cause any radical modification of the funda- 

 mental principles involved. Where such advances have 

 come within the scope of a book of this character an 

 effort has been made to present them, but the original 

 aim and object of the book have been maintained. 



The author wishes to acknowledge his indebtedness 

 to the writers of the many flattering reviews that " The 

 Principles of Bacteriology" has received, and hopes 

 that in future, as in the past, readers will continue to 

 favor him with criticism and suggestions that may serve 

 to further enhance the value of the work. 



A. C. A. 



PHILADELPHIA, NOVEMBER, 1895. 



208314 



