CHAPTER VI. 



THE METHODS EMPLOYED FOR INVESTIGATION OF CHEMICAL 

 CHANGES WITHIN THE ANIMAL OKGANISM. 



Introduction. 



IN the foregoing pages attention has been directed almost 

 entirely to the consideration of the structure of organic 

 compounds. An intimate acquaintance with this structure 

 is essential before any progress can be made in the study 

 of the various anabolic and catabolic processes which 

 take place within the living organism (see p. 10). It is 

 not surprising, therefore, that the state of knowledge of 

 the chemical changes which take place in the living organ- 

 ism falls far below that of the transformations which can 

 be accomplished in the apparatus of the laboratory, as 

 a systematic investigation of the biological aspects of 

 chemistry, or what is commonly known as physiological 

 chemistry, can only commence when the study of the 

 structure of the constituents of living objects is compara- 

 tively far advanced. 



It must be admitted that, up to the present time, the 

 advances made in the study of chemical transformations 

 taking place within the bodies of living objects have been 

 comparatively slow, in spite of the large number of workers 

 who have been attracted to the investigations ; and in con- 

 nection with this statement it is of interest to note that 

 one journal alone dealing with biological chemistry pub- 



