10 INTRODUCTORY 



majority, of the vital products hitherto synthesised are of the nature of 

 down-grade materials, or, in other words, waste products resulting 

 from the degradation of more complex antecedent compounds. It is 

 probable that in many cases the waste material is a final product of the 

 breaking down of several different antecedent compounds. 



For the foregoing reasons the term synthesis as used in this work 

 has been given a wider meaning so as to comprise both up-grade and 

 down-grade products. From the established point of view, for example, 

 the formation of acetic acid from methane via methyl chloride and 

 cyanide, &c., is regarded as a true synthesis, the simpler molecule 

 having given rise to the more complex. But from the present point 

 of view the formation of methane from acetic acid by heating acetates 

 with alkali is just as much a true and complete synthesis of methane 

 as is the formation of this hydrocarbon by the direct union of its 

 elements. The methane of vital origin is a bacterial product resulting 

 from the breaking down of an extremely complex molecule, cellulose. 

 The latter has not yet been synthesised, but if this synthesis should 

 ever be effected the synthesis of methane via cellulose would be as 

 complete as the synthesis of the hydrocarbon via acetic acid. 



The enlarged view of chemical synthesis thus rendered necessary 

 by a contemplation of the facts from the biological standpoint has 

 resulted in a mode of treatment which may at first seem strange and 

 unfamiliar, but it will be found that the method on closer acquaintance 

 is one that cannot but be helpful to chemists as well as to technologists. 

 Not only is prominence given thereby to the actual generators of the 

 various synthesised products, but the inter-relations between the 

 organic compounds themselves is also brought out as a special feature 

 to which, in view of the importance of the subject, emphasis is given 

 by means of the sub-title of the book. 



The interest of the present work will, it is anticipated, be found 

 to centre not only in the records that particular compounds can be 

 obtained from such or such generators, but, as already pointed out, 

 more particularly in the information that such compounds are geneti- 

 cally related among themselves. Thus, to take a simple illustration, the 

 relationship of alcohol to aldehyde and acetic acid is of more .than 

 purely chemical interest in this work ; it is a fact also of biochemical 

 interest, because aldehyde and acetic acid are both vital products, and 

 the relationship is further of technological interest because the acid is 

 industrially producible from the alcohol by biochemical processes. In 

 general terms the genetic relationship of an organic compound to 

 a product sometimes of greater and sometimes of less complexity is 

 a fact which the present mode of treatment is well adapted to reveal, 

 and the essential feature of this treatment is to bring out all such 

 inter-relations within the limits of a reasonably sized work. In many 

 cases, such, for example, as the relationship of alcohol to certain sugars, 

 the living organism may be said to have discovered methods of break- 



