X INTRODUCTION 



always be foreseen or determined. It is well to remember, too, that 

 such .'aggregate subjects as Agriculture and Domestic Science, unlike 

 Engineering and Medicine, because of their youth, have not developed 

 to that stage in their educational history where practice and the science 

 upon which practice should be founded are amalgamated. The practi- 

 cal man in Agriculture, and Applied Sciences generally, too frequently 

 is so extremely traditional in his practice that he utterly fails to separate 

 the true from the false, or, in other words, does not exercise his dis- 

 criminative powers at all, but depends entirely upon so-caUed haphazard 

 methods and self-willed processes. This factor operates against the 

 proper development and logical study of any branch of science in its 

 relation to the farmer, or manufacturer. 



The plan of a text-book in Microbiology which seeks to furnish 

 basic principles, to train the mind in logical development and adjust- 

 ment, and to prepare the student to undertake an intelligent study of 

 strictly professional or practical subjects, must assume a definite and 

 systematic arrangement. With this in mind, the text has been divided 

 into three distinct parts: Morphological and Cultural, or that which 

 deals with forms and methods of handling; Physiological, or that which 

 deals strictly with functions, the key to the applied; Applied, or that 

 which reaches into the application of the facts developed to the problems 

 met in the study of professional or practical affairs. 



In a text-book, the product of several hands, there is the most serious 

 difficulty in obtaining unity of thought and expression without repeti- 

 tion; besides, that very conspicuous weakness of emphasizing some fea- 

 tures unduly while other features of importance are scarcely mentioned, 

 confronts us. A most earnest attempt has been made to overcome 

 these faults as far as possible, but' a complete mastery of them cannot 

 be expected in the first product. However, what is lacked in unity 

 and continuity of expression and in balance we sincerely hope will be 

 made up, in part at least, by the selection and the value of the material 

 contributed. 



Laboratory features of microbiology have been eliminated wher- 

 ever it has been practicable. Should any demonstration be added 

 or needed, we have felt that they may be easily supplied by the instruc- 

 tor, who, of course, will be governed by local facilities and conditions. 

 Although no space has been given to laboratory exercises, is should not 

 be gathered that the authors of this book are any the less earnest in 



