172 THE ANATOMY OF SCIENCE 



that wonderful story that upon the approach 

 of a stranger all the inhabitants catch cold; 

 but that it had been so well authenticated he 

 determined to retain it." 



Organic chemistry is one of the less mathe- 

 matical sciences. The whole theory of structure 

 requires about as much mathematics as a child 

 needs for building houses with blocks, and while 

 the balance has been a useful adjunct, exact 

 analysis has served rather as a corroboratory 

 than as a primary method of research in or- 

 ganic chemistry. The science has grown, like the 

 biological sciences, through a dual method of 

 classification. On the one hand, we study the 

 actual properties of substances; on the other, 

 their genetic relations. From a familiar sub- 

 stance a new one is made, from this another. 

 Some of these products can be prepared from 

 other initial substances, and so these threads of 

 interlocking relationships have been woven 

 through the whole complex material. 



The atomic theory made it possible to pre- 

 pare models, first of the simpler and later of 

 the more complicated molecules. The rules of 

 this kind of architecture are illustrated in Fig- 

 ure 25. A hydrogen atom (indicated by H) has 

 one point of attachment, the oxygen atom (O) 



