CHEMISTRY 195 



that the anatomical characteristics of one 

 class of animals distinguish such a class from 

 other classes of animals. In short, the carbon 

 compounds are not unique merely because 

 they are numerous ; they are uniquely nu- 

 merous because they are compounds of carbon 

 with hydrogen, oxygen, and in some cases 

 certain other elements. They possess, more- 

 over, other less obvious class properties as 

 well, though of these, it must be admitted, 

 chemistry is even yet far from a clear under- 

 standing. But unquestionably that is due 

 to the incompleteness of the science, for the 

 peculiar methods of organic chemistry are a 

 sufficient guarantee of the existence of such 

 class peculiarities. 1 



In our present investigation a study of the 

 possibilities of chemical union between the 

 elements carbon, hydrogen, and oxygen is of 

 great importance, and accordingly we must 

 now examine some of the results of synthetic 

 organic chemistry. 



1 See the introductory chapter to Meyer and Jacobson's 

 "Lehrbuch der Organischen Chemie," Leipzig, 1907. 



