CHAPTER II 



OUTLINES OF BACTERIOLOGICAL TECHNIQUE 



Bacteriological and enzyme chemistry is essentially the 

 chemistry of the single cell ; biological chemistry and physio- 

 logical chemistry in the wider sense deal with the changes 

 taking place in higher organisms, which consist of collections 

 of cells of varying and interdependent functions. We have 

 therefore only to consider the chemical changes brought 

 about by the simplest organisms, which if not actually 

 unicellular are only very slightly difierentiated ; or with 

 the chemistry of specific cells of higher organisms. More- 

 over, from the chemical point of view, the form of the 

 organism, and its method of growth and development, are 

 of less importance than the chemical changes it brings 

 about. 



The following pages deal with the methods of recognition 

 and cultivation of the simplest organisms, the subject being 

 treated in quite a general manner. For the detailed methods 

 used in the recognition of specific organisms, text books on 

 bacteriology should be consulted. 



The micro-organisms whose chemical activities have to be 

 studied may be divided into three groups, viz. : — 



I. Bacteria ; 

 II. Yeasts ; 

 III. Moulds. 



Bacteria (Fig. 3, 1, and I^).— These are the lowest forms of 



