PREFACE TO THE FIRST EDITION. 



THE present work has been prepared to give the 

 nurse and the beginner an idea as to the nature of 

 microorganisms and their relation to the world's 

 economy, especially in disease. For this reason much 

 technical material has been omitted, especially in the 

 subject of biological differentiation. Emphasis has 

 been laid upon how bacteria pass from individual to 

 individual, how they enter the body and act when 

 once within, and their manner of exit. Such general 

 information concerning the character of the disease 

 process has been included as seemed necessary to 

 clarify the nature of the microbe action. Indeed, the 

 subject matter in many places is but elementary 

 bacteriological pathology. During the preparation of 

 the work the author has had in mind a question he 

 has been asked repeatedly: How do bacteria produce 

 disease? That this question is answered as simply 

 and as well as our knowledge of today permits is 

 the author's sincerest hope. 



H. F. 



