BIOCHEMISTRY 



CHAPTER I 

 BIOTIC STRUCTURE AND BIOTIC ENERGY 



BIOCHEMISTRY may be defined as the study of the chemical sub- 

 stances produced by biotic energy that is, the energy of life in the 

 bodies of living plants and animals, and the further study of the 

 energy processes by which such substances are elaborated and used 

 subsequently to their production for carrying on the life of the cell. 



While it may be true that the living cell and its energy exchanges 

 are rigorously subject to physical and chemical laws, it is also true 

 that such structures as obtain in living matter are nowhere in 

 nature found reduplicated save in living matter, and this peculiarly 

 constructed living matter is inhabited by a type of energy bound 

 to living matter, and not producible in its absence. 



This type of energy, the machine or transformer which produces 

 it, and the chemical substances manufactured in the course of the 

 operations, form together the field for the study of biochemistry. 



Our knowledge of the subject is still in its infancy, and much 

 remains to be discovered, so that any presentation must be 

 fragmentary ; yet in spite of this the wealth of detail in known parts 

 of the subject is already so great that a selection becomes necessary 

 to illustrate a general review of the subject. 



The mystery which surrounds the processes of lif e, like the mist 

 on mountain-tops, leaves room for speculation and imagination, 

 and enhances the charm and beauty of a present-day study of this 

 young and vigorous branch of modern science. 



Viewed from the physico-chemical point of view, the living cell 

 is a peculiarly constructed energy machine or energy transformer, 

 through which a continual flux of energy ceaselessly goes on, and 

 the whole life of the cell is an expression of variations and alterna- 

 tions in the rates of flow of energy, and of changes in the equilibria 

 or balances between various types of energy. 



Like all other energy discharges, life as a whole is phasic or 

 oscillatory in character. In the organic world the phases or 



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