240 ORGANIC AGRICULTURAL CHEMISTRY 



seems probable, and is pretty generally accepted, that formalde- 

 hyde is first produced and is immediately further transformed 

 into carbohydrate. Fincke,^ however, claims that the forma- 

 tion of glycolic aldehyde, CH2OH — CHO, as an intermediate 

 product is in closer agreement with known facts. 



One further point in connection with this step in the photo- 

 synthetic process is that the other product of this laboratory 

 synthesis, viz. oxygen, is also the other product of the reaction 

 as it takes place in plants. When carbon dioxide is assimilated 

 by plants, oxygen is given off, and this evolution of oxygen is 

 directly proportional to the photo synthetic activity. The absorp- 

 tion of carbon dioxide and evolution of oxygen by plants was 

 originally taken to indicate that the life process in them was 

 directly the opposite of that in animals. This we now know 

 to be wrong, for, as we have shown, the living process of the 

 cell and the utilization of its food for the liberation of energy, 

 with the excretion of carbon dioxide as one of the products of 

 the oxidation reaction, is alike in both plants and animals. 



The other part of the double reaction representing the synthe- 

 sis of glucose from carbon dioxide and water, viz. the polymeriza- 

 tion of formaldehyde to glucose, is one of which there is no 

 doubt as a laboratory reaction and also one that is perfectly 

 possible in the living plant. 



We must emphasize the fact, however, that because we have 

 a right to express by these reactions a known laboratory synthe- 

 sis, this does not establish the fact that the same synthesis takes 

 place in plants. Other reactions have been established in the 

 laboratory which make it also possible that from the same 

 original substances fats may be synthesized and even proteins, 

 provided nitrogen compounds are supplied from the soil. All 

 plant physiologists and chemists have not yet accepted it as 

 proved that formaldehyde is present in plants nor that it is 

 the actual intermediate product in carbohydrate synthesis. 

 We know beyond question this much only: (i) The end prod- 

 ucts of the reaction of photosynthesis are on the one hand 



^Fincke, Z. Nahr. Genuss., xxvii, 8 (1914). 



