AUTHOR'S PREFACE 



SEEING that there is at the present time no lack of treatises 

 upon bacteria, the publication of yet another needs some apology. 

 Such an apology is expressed in the title, Lectures on Bacteria *. 

 The lectures are intended to be an introduction to general bac- 

 teriology. They purpose to give a survey that shall collect and 

 condense the innumerable special researches into a connected 

 whole, and indicate in broad outlines the present position and 

 extent of bacteriological science. 



Besides those medical aspects of bacteriology which in other 

 treatises occupy, rightly enough, the chief place, attention is drawn 

 to the importance of bacteria in agriculture, and to the parts they 

 play in the great fundamental processes of life the circulation of 

 nitrogen and carbon dioxide. Furthermore, it seemed desirable to 

 point out and emphasize the advancement that general physiology 

 has received from bacteriological investigations. Finally, an 

 attempt has been made to remove the bacteria from the isolated 

 position to which their morphological and physiological pecu- 

 liarities had relegated them, and, by comparative studies, to 

 indicate their relations to other organisms. 



A treatment of the subject on these lines that should be at the 

 same time not too bulky, seemed to me to be wanting. I there- 

 fore undertook the publication of the course of lectures I have 

 delivered for some years to students of biology, pharmacy, and 

 agriculture, with here and there among them as it were like a 

 white raven ! a medical student. 



ALFKED FISCHER. 

 LEIPZIG, 



22 July, 1897. 



* The title of the German work is Vorlesungen iiber Bakterien, 



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