SYNTHETICAL CHEMISTRY 17 



compounds have been discovered during the compilation of this work 

 are too numerous to select special illustrations from ; constant interpo- 

 lations have, as already stated, been necessary to keep pace with the 

 progress of discovery. 



In pursuance of the scheme of recording the inter-relations between 

 organic compounds on biochemical rather than on purely chemical 

 lines it has also been found necessary, not only to interpolate whole 

 series of intermediate stages irrespective of practical considerations, 

 but also to record synthetical processes which in many cases yield only 

 a small quantity, or even only a trace, of the final product. In other 

 words, the question of yield, like the question of directness of method, 

 cannot be allowed any weight in presenting the subject of chemical 

 synthesis from the present point of view. It is clear that we are 

 following the natural method in this, because it is tolerably certain 

 that a large number, if not a large majority, of the vital products at 

 present isolated and synthesised are of the nature of by-products, 

 having no quantitative relationship to their generators that could be 

 stated even if we knew what these generators were in the form of 

 chemical equations which could be said to express the whole truth. 

 No less is it certain that many of the vital compounds herein dealt 

 with arise from the breaking down of many antecedent generators, 

 and the final product results from the accumulation of traces of the 

 compound derived from several sources. 



It may fairly be urged that the inclusion of processes which result 

 only in a trace of the final product diminishes the value of this work 

 from the technological point of view. Even here, however, it is 

 claimed that the biochemical method, if properly used, may be of great 

 service in chemical technology. In using this as a work of reference 

 in which all the generators of any particular compound are recorded 

 in a systematic manner, the chemist, the physiologist, and the techno- 

 logist will no doubt each use his judgement in assigning due weight 

 to any particular process. The mere statement of the fact that there 

 is any genetic relationship between one compound and another of 

 industrial importance may furnish a suggestive clue for future in- 

 vestigation. As our knowledge of biochemical processes advances and 

 as our chemical processes are brought more and more into line there- 

 with, it is certain that the manufacture of vital products will derive 

 just as much advantage as will the laboratory methods for synthesising 

 organic compounds which are of no industrial use. 



To state the case another way, the fact that a particular generator 

 gives rise to only a trace of some compound of industrial use is a hint 

 given by Nature that the future technologist might work upon to 

 increase the yield and, as it were, to improve upon Nature's own 

 method. The history of the development of industrial organic 

 chemistry furnishes many examples which justify this inclusion of 

 all processes, irrespective of yield. In modem times the synthesis of 



