The photosynthesis of naturally occurring compounds. I.—The action of ultra-violet light on carbonic acid

Abstract

In a preliminary paper one of us, in conjunction with Prof. Heilbron and Prof. Barker, described some observations on the action of ultra-violet light on pure aqueous solutions of carbonic acid. It was found that traces of formaldehyde were present in these solutions after insolation, provided that a stream of the gas were passed through the water during the exposure to the light. These results differed from those which had previously been recorded by Moore and Webster, who had stated that the presence of a catalyst such as colloidal ferric or uranium hydroxide was necessary. The observation by Moore and Webster that formaldehyde in aqueous solution is converted by ultra-violet light into reducing sugars was fully confirmed, and the view was put forward that the mechanism of the photosynthesis of carbohydrates from carbonic acid consisted of two stages, first, the formation of formaldehyde, and, second, the conversion of this substance into hexoses.