PKEEACE 



THE subject of bacteriological and enzyme chemistry is 

 becoming year by year of increasing importance. A know- 

 ledge of it is now necessary for the scientific conduct of many 

 industrial processes of great magnitude. 



Apart from its well-known applications in the fermen- 

 tation industries, a scientific understanding of this branch 

 of chemistry is likely to exercise considerable influence upon 

 the future development of agriculture. 



Recent advances in sanitation, especially the provision of 

 pure water, and the inoffensive disposal of sewage, call for 

 the co-operation of the engineer and the biological chemist. 



The Institute of Chemistry has recognised these require- 

 ments in the special examination in biological chemistry, 

 which it has conducted for a number of years past. The 

 author's students have frequently asked him to recommend 

 an elementary book, which should serve as an introduction 

 to the somewhat overwhelming literature of the subject. 



The difficulty of pointing to any one work which satisfied 

 these requirements led the author to attempt himself to 

 supply the deficiency. 



In writing the book he has had in mind, not only the 

 purely chemical student, but also members of other pro- 

 fessions, with whom he has frequent occasion to co-operate, 

 notably the engineer and medical officer of health, as well 

 as the general reader, to whom the subject offers many 

 attractions. 



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