524 PROTOPLASM 



back into the sea. The best illustration of this aquatic adapta- 

 tion of an animal whose ancestors were terrestrial is the reptile 

 Ichthyosaurus. But our problem dates back earlier than the 

 origin of living forms. 



The first organic substance produced on earth may have been 

 sugar or some substance intermediate between carbon dioxide, 

 water, and sugar. The artificial production of sugar has long 

 occupied the attention of chemists and biologists, not so much 

 because of its bearing on the theoretical question of the 

 origin of life but primarily as a solution of the secret of photo- 

 synthesis by plants and the commercial imitation of it on a profit- 

 able scale. The German chemist Emil Fischer was the first to 

 synthesize sugar in the laboratory, but his methods were very 

 complex. The English chemist E. C. C. Baly has gone at the 

 problem in imitation of nature. Some years before Baly, his 

 fellow countryman Benjamin Moore, a pioneer in the chemistry 

 of life and an ardent advocate of the view that it was meaning- 

 less to predicate the existence of a vital force to explain phe- 

 nomena of which the chemistry and physics were not understood, 

 succeeded in synthesizing formaldehyde from carbonic acid and 

 water, using colloidal iron oxide as the catalyst and artificial 

 light of very short wave length as the energy. At least, he is 

 credited with the experiment and a subsequent one in which he 

 accomplished the same result with ordinary sunlight, using a 

 pigment such as methyl orange to act as catalyzer of the chem- 

 ical change. As formaldehyde is believed to be a stage in the 

 process by which green plants build up sugars and starches from 

 carbonic acid and water, Moore's experiment was apparently a 

 definite step in artificial photosynthesis. Today, the results 

 claimed by Moore would be questioned. 



Some years later, Baly and his colleagues announced that 

 they had succeeded in converting water and carbonic acid into 

 formaldehyde, and the formaldehyde into sugar, using the 

 energy of ultraviolet light. A stream of carbon dioxide was 

 passed through water containing a fine colloidal suspension of a 

 metal (aluminum) or a salt (nickel carbonate) and exposed to 

 sun or artificial light. Uncertainty exists on numerous points — 

 e.g., on whether the first product formed through the action of 

 ultraviolet light on carbonic acid, H2CO3, is formaldehyde, 

 CH2O, which is presumably activated by light and polymerized 



