226 THE FITNESS OF THE ENVIRONMENT 



and mannose are produced, and, all told, the 

 constituents of such a solution probably 

 number at least two hundred, all produced 

 from glucose alone, under the influence of a 

 slight excess of hydroxyl ions. Among these 

 substances the greatest diversity of chemical 

 behavior is to be distinguished. Alcohol, 

 aldehvde and ketone, and acid radicals occur 

 in great profusion and variety of combinations ; 

 compounds possessing forked chains are pres- 

 ent ; and double bonds between carbon atoms 

 add to the complexity. Moreover, all these 

 substances themselves possess great chemical 

 activity. 



A single case may perhaps illustrate this 

 point. It has been shown by Windaus and 

 Knoop l that in such solutions, in the presence 

 of ammonia, one molecule of methyl glyoxal, 

 one of formaldehyde, and two of ammonia 

 unite to form the cyclic compound, methyl 

 imidazol, a substance related to histidine, 

 the latter being an important constituent of 

 the protein molecule : — 



CH 3 -C = NH 3 / H CH 3 -C-N/H 



I C^O -> II ^>C-H 



C=0 NH 3 X H H— C-N^ 



H 



1 Knoop and Windaus, Berichte, XXXVI, 1166, 1905. 

 Hofmeister's Beitrage, VI, 392, 1905. 



