JANXTABY 27, 1911] 



SCIENCE 



133 



sible, its standing in the light of moclern 

 discoveries. 



In 1861 there appeared in the Annalen 

 der Chemie and simultaneously in the 

 Comptes rendus a short article by a Rus- 

 sian chemist, Butlerow," in which he de- 

 scribed the formation of a sugar-like 

 substance (methylenitan, he termed it) 

 through the interaction of trioxjonethylene 

 and calcium hydroxide in an aqueous solu- 

 tion. Although the resulting substance 

 was optically inactive and was not fer- 

 mentable, Butlerow nevertheless was sure 

 that the sweet syrup which he obtained 

 contained a sugar, for he concludes his 

 accounts with the statement that his results 

 furnish the first example of the synthesis 

 of a sugar-like body. These results of 

 Butlerow proved to be of the greatest im- 

 portance, not only because of the facts re- 

 vealed, but also because they served to sug- 

 gest to other investigators the method of 

 attacking the general problem of the syn- 

 thetic production of sugars. Moreover, 

 they undoubtedly served as an experi- 

 mental groundwork upon which Baeyer a 

 few years later based his well-known 

 hypothesis. 



The essential assumptions of Baeyer 's 

 hypothesis, viz., the production of formal- 

 dehyde through the interaction of carbon 

 dioxide and water, and the subsequent 

 polymerization of this to a sugar, are well 

 known to all and require no discussion. 

 It may be of interest, however, to recall 

 some of the reasons advanced by Baeyer in 

 setting forth these assumptions. 



The original statement of the theory was 

 published in the Berichte just forty years 

 ago (1870) and was entitled "Ueber die 

 Wasserentziehung und ihre Bedeutung 

 fiir das Pflanzenleben un die Gahrung."^ 



° Annalen der Chem., 120, p. 295 ; Compt. rend., 

 53, p. 145. 



'' Ber. d. chem. Gesell., 3, p. 67, 



Baeyer here calls attention to the fact 

 that in the transformation of the com- 

 pounds of carbon, hydrogen and oxygen, 

 the separation of water plays just as 

 weighty a role as do the processes of oxida- 

 tion and reduction. He then discusses the 

 groups of those reactions in which water is 

 formed by the union of hydrogen and 

 oxygen withdrawn from the interacting 

 compounds. Among the various reactions 

 are those in which the water removed is 

 formed by the union of hydrogen taken 

 from one molecule with an hydroxyl group 

 taken from a different molecule — an "aus- 

 sere Condensation," as Baeyer termed it. 

 To illustrate this he gives his interpreta- 

 tion of the reaction involved in Butlerow 's 

 sugar synthesis. Although Butlerow had 

 used trioxymethylene, Baeyer evidently felt 

 justified, because of the intimate relation 

 between this compound and formaldehyde, 

 in assuming that the reaction actually 

 taking place is one between the different 

 molecules of formaldehyde. Considering 

 that formaldehyde in aqueous solution is 

 in the hydrated form, Baeyer shows that 

 by the splitting off of water formed by the 

 union of a hydroxyl group from one mole- 

 cule of formaldehyde with the hydrogen 

 from another molecule and the union of 

 the two remaining residues through the 

 resulting free affinities, it is easy to under- 

 stand how from six molecules of formalde- 

 hyde the hexoses might result. Baeyer 

 even deduced two possible structural for- 

 mulas for a hexose based on this interpre- 

 tation of the course of the reaction, one of 

 these being the well-known aldehyde for- 

 mula. Likewise he shows how by the con- 

 densation of three molecules of formalde- 

 hyde one would expect to obtain an alde- 

 hyde of glyceric acid. The older view of 

 Liebig to the effect that the fruit acids are 

 the intermediate products from which the 

 sugars result, Baeyer rejects in favor of 



