SYNTHETIC WORK IN CARBOHYDRATES 319 



prises the notion that the conceptions of the science advance 

 with the unfolding of its parts. 



The evolution of chemical compounds is theoretically illus- 

 trated by the building of more complex compounds from sim- 

 ple compounds, themselves formed from the elements, which, 

 no doubt, in turn come from still simpler sources. The com- 

 plex bodies of the same type, as, for instance, the hydrocar- 

 bons of the fatty series, show development on their own lines. 

 Passing from the fatty hydrocarbons to those of the aromatic 

 series is another example and indication of progress to syn- 

 theses beyond. In the laboratory these processes no doubt 

 oftentimes are carried out by circuitous methods, as Nature's 

 sequences in these particulars are unknown. In the natural 

 changes that rocks, plants and animals undergo, a self-direc- 

 tive chemical consciousness, adequate to the needs of the re- 

 spective conditions, doubtless obtains. 



There was a time, not so long ago, when many of the chem- 

 ical compounds resulting from the chain of existence were 

 isolated from animal and plant life. The key of chemical change 

 was looked for in the study of plants, and to these sources, 

 from life, chemists turned for new research fields. 



A little later, chemical synthesis, or the production of com- 

 pounds by artificial means, had its beginning. From time to 

 time, at longer or shorter intervals, appeared the announce- 

 ment of the synthesis of some compound hitherto derived from 

 plant or animal life. But the later years of this century, from 

 the chemical point of view, may be regarded specially as syn- 

 thetic years, ever nearing the zenith of greater attainment. 



The subject of sugars early attracted the attention of chem- 

 ists, not only because of the industrial aspects, but also, be- 

 ing one of the main divisions of the classification of compounds, 

 the study of its varieties and composition has been untiringly 

 pursued. The vision arose in the long past of its possible syn- 

 thesis. Liebig first conceived the idea of making sugar arti- 

 *fitially. But the synthesis of this important group of com- 

 pounds defied all efforts until comparatively recent times. 

 The first mixture of synthetical sugars was obtained by Butle- 



