228 THE FITNESS OF THE ENVIRONMENT 



hydrogen in one molecule, and so that, further, 

 the relative proportions of the three elements 

 may become what they are in the simple 

 carbohydrates, C:H:0 = 1:2:1. 



(2) Somehow individual carbon atoms must 

 be joined together until there are six in each 

 molecule, where formerly there was but one. 



Theoretically, it might be possible by reduc- 

 tion to form from carbon dioxide and water 

 without union of carbon atoms the following 

 substances : carbon monoxide, CO ; formic 

 acid, HCOOH; formaldehyde, HCHO; 

 methyl alcohol, CH 3 OH ; and methane, CH 4 . 

 Of such reductions the formation of formic acid, 

 formaldehyde, and carbon monoxide has been 

 directly realized by laboratory experiment. 1 



The most familiar theory of the formation 

 of carbohydrates in the leaf is that of von 

 Baeyer, which assumes a polymerization of 

 one of the above substances, formaldehyde, 

 leading directly to the formation of sugar, 

 according to the reaction 



6HCHO = C 6 H 12 6 . 



This process also has been carried out ex- 

 perimentally. Indeed, as a result of the 

 investigations of Butlerow, O. Loew, and 



x See Meyer u. Jacobson's "Lehrbuch der Organischen 

 Chemie," Leipzig, 1907, p. 688, 693-696. 



