CHAPTER VIII 

 Physiological and Biochemical Technics 



R. D. DeMoss and R. C. Bard 



INTRODUCTORY 



Even the bacteriologist not experiencing repeated contacts with micro- 

 bial biochemistry is aware of the vast accumulation of knowledge in this 

 field during recent years. Indeed, the methods and interpretations of 

 microbial biochemistry have attained leading roles in modern micro- 

 biology, and as a result of this position, the importance of these phases of 

 study in the training of new workers and in current research can hardly 

 be overemphasized. 



The main guiding principle during the preparation of this chapter has 

 been the concept of environmental adaptation. The extreme adaptabil- 

 ity and response of bacteria allow the choice of specific growth conditions 

 in order to understand more easily and more completely a given bio- 

 chemical situation. Thus, the premise has been adopted which demands 

 a thorough study of physiological conditions relating to a specific bio- 

 chemical process prior to a detailed investigation of that biochemical 

 process. Accordingly, the following technics apply to physiological 

 studies, often requiring a measurement of growth, and to both general 

 and specific biochemical reactions. The material presented will deal 

 primarily with bacteria, although investigations with algae, molds, 

 protozoa, and even viruses along similar lines are being pursued vigor- 

 ously and a unity of concept is being formulated. 



The methods described in this chapter are not in general applicable to 

 routine work in the sense of taxonomic investigations (see Chap. VII). 

 In some cases these technics represent an extension of the routine tests, 

 while the majority of the methods, because of the requirement for more 

 precise and detailed measurements, are based upon different principles 

 and usually depend upon instrumentation in addition to visual 

 observation. 



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