SECTION B.— CHEMISTRY. 



THE SCOPE OF ORGANIC CHEMISTRY. 



ADDRESS BY 



PROF. J. F. THORPE, C.B.E., D.Sc, Ph.D., F.R.S., 



PRESIDENT OP THE SECTION. 



The chemistry of the compounds of carbon covers a wide field, wider 

 than that covered by any other element. Its scope embraces all living 

 matter, as well as the vast number of non-living substances which are 

 produced through the agency of life. Moreover, it includes a very great 

 number of compounds unrelated to life or to living processes which have 

 been built up by the chemist in the laboratory by methods he has devised. 

 Already some 200,000 definite compounds have been tabulated in 

 Richter's Lexicon and in the supplements thereto, and this number is 

 increased yearly by several thousands through the agency of a band of 

 zealous workers scattered over the globe. It may well be asked what is 

 the good of continuing to increase this already astonishing number ; and 

 is the expenditure of time, labour and energy justified which leads to the 

 discovery of some new fact having, apparently, no useful application to 

 any department of human activity ? The answers to these questions are 

 quite clear and definite. You must acquire a knowledge of the simple 

 before you can attack the complex with any hope of success. The element 

 carbon has been used by nature as the basis of organised life because the 

 capacity of carbon to combine with itself is shared by no other element, 

 and it is upon this capacity that nature has relied in order to build up 

 the tissues and reserve materials which form the living world around us. 

 Moreover, since the compounds of carbon containing a moderate number 

 of atoms of the element are usually crystalline or capable of becoming 

 crystalline, and there are obvious disadvantages attaching to the use of 

 potsntially crystalline substances as the basis of living matter, it has been 

 found necessary to employ the more complex carbon derivatives con- 

 taining many hundreds of elemental atoms, which by reason of their 

 high molecular complexities no longer possess, or seem capable of acquiring, 

 a crystalline structure, but belong to the class of jelly-like or colloidal 

 substances. Until we can determine how a small number of carbon atoms 

 combine one with the other we cannot hope to obtain any insight into 

 the manner in which the more complex natural substances are built up, 

 or any information regarding the way in which they are utilised to bring 

 about the changes occurring during animal and vegetable metabolism. 



Structure. 



The science of structural organic chemistry is only just fifty years old. 

 It was born when the genius of van't Hoff gave to the world the clue upon 

 which the three-dimensional formula we now use is based. It is, therefore, 



