60 ANIMAL CHEMISTRY LECTURE III. 



acid C 2 H 2 C1 2 2 , monochlor-acetic acid C 2 H 3 C10 2 , and finally into 

 normal acetic acid C 2 H 4 O ?> . In concluding his account of these 

 singular transformations, Kolbe remarked with great prescience : 

 ' From the foregoing observations we deduce the interesting 

 fact that acetic acid, hitherto known only as a product of the 

 oxidation of organic materials, can be built up by almost direct 

 synthesis from its elements. . . . If we could but trans- 

 form acetic acid into alcohol, and out of the latter could obtain 

 sugar and starch, we should then be enabled to build up these 

 common vegetable principles, by the so-called artificial method, 

 from their most ultimate elements.' 



(62.) Kelying upon these results, Laurent in his ' Methode de 

 Chimie,' 1853, and Hofmann in a course of lectures l On Organic 

 Chemistry,' delivered the same year at the Royal Institution, the 

 latter, with very great detail, showed how impossible it was to 

 draw the line of demarcation between carbon compounds of or- 

 ganic, and carbon compounds of mineral origin. They both 

 referred to Kolbe's formation from mineral elements of acetic 

 acid or vinegar, and of certain highly complex bodies procurable 

 from vinegar, such as mesidine C 9 Hj 3 N, and nitro-mesidine 

 C 9 H 12 N 2 O 2 . It must be admitted, however, that to .the labours 

 of Berthelot, prosecuted unintermittingly for the last ten years, 

 is due that full recognition of synthetic organic chemistry which 

 now obtains, and the very great advances recently made therein 

 both by himself and by others, which I purpose hereafter to 

 bring under your more especial consideration. 



Before proceeding, however, to exemplify the powers of organic 

 synthesis in the artificial formation of animal and vegetable pro- 

 ducts from carbon, hydrogen, and oxygen, I must beg leave to 

 make a rather long digression. I propose, firstly, to bring before 

 you some elementary experiments connected with the production 

 and decomposition of the oxides of carbon and hydrogen, or car- 

 bonic anhydride CO 2 , and water H 2 O, respectively ; and then to 

 consider with you what bearing these experiments have upon the 

 forces exerted in animal and vegetable life, or, in other words, 

 upon the so-called vital forces. 



