22 VELOCITY OF REACTIONS 



letting ultra-violet light act upon glucose in the 

 presence of bases, such as caustic soda, ammonia or 

 lime water. 



Before the nineteenth century it was believed 

 that some products of animals or plants could not 

 be prepared without the interaction of life-processes. 

 Wohler in 1828 was the first to break down this 

 belief, when he prepared urea from ammonium- 

 cyanate. The synthesis of alizarin by Graebe and 

 Liebermann (1869), ofindigo by Baeyer (1878), and 

 still more of the fats by P£louze and G£lis (1843) 

 and Berthelot (1854), and of the different sugars 

 by Emil Fischer (1890), who has even succeeded 

 in building up polypeptides, giving the reactions 

 of albuminous substances, and a multitude of other 

 syntheses, have completed this work in the most 

 striking manner. It is now generally recognized 

 that the synthesis of organic products from inorganic 

 matter will always be possible if we devote sufficient 

 work to the solution of this question, and even that 

 the tools of the chemist surpass the living organism 

 in multiplicity of effects. Ultra-violet light and the 

 silent discharge of electricity are in this special case 

 very mighty factors. The enormous success in this 

 domain has created the conviction that we are 

 complete masters of these problems, and that in 

 the course of time we shall be able to prepare 

 synthetically any product of Nature, living or 

 inanimated. 



But a given compound may be produced in 

 many different ways, and it is therefore very possible 



