200 SCIENCE PROGRESS 



HO . CH : NOK + HgO), and in a series of papers describes a 

 number of experiments in which he obtains evidence of the 

 formation of complex nitrogenous plant products by photo- 

 synthesis. For example, by the action of ultra-violet light 

 on potassium nitrite solution in the presence of carbon dioxide 

 with ferric chloride as a catalyst he obtained evidence of the 

 formation of amino-acids, and in solutions of potassium nitrite 

 and formaldehyde exposed to ultra-violet light, of an alkaloidal 

 compound similar to nicotine. Baly, Heilbron, and Hudson, 

 working in a rather more systematic manner, have obtained 

 similar results, and by the assumption of the formation of an 

 active form of formaldehyde containing bivalent carbon have 

 suggested an ingenious mechanism for the synthesis of nitro- 

 genous plant products. 



The conception of activated formaldehyde is new to this 

 paper, and the authors consider that, by the action of ultra- 

 violet light, formaldehyde is converted into an active form 

 which, in the absence of other reagents, at once undergoes 

 polymerisation to sugars. They go on to state that this active 

 phase is the same as that which is the first product of the 

 photosynthesis of formaldeh3^de from carbonic acid, and there- 

 fore in the living plant sugars are produced directly without 

 the actual formation of the ordinary non-reactive molecules 

 of formaldehyde. This seems to introduce an unnecessary 

 confusion. In the previous paper Baly, Heilbron, and Barker 

 showed that by absorbing rays of greater wave-length than 

 290ya/i, which they showed brought about the polymerisation 

 of ordinary formaldehyde to sugars, the aldehyde could be 

 obtained in quantity by the action of ultra-violet light on 

 solutions of carbon dioxide. As under the normal conditions 

 of plant growth the polymerising rays are also present, the 

 failure to detect formaldehyde in leaves is easily explicable, 

 but the very fact that light of a different wave-length is re- 

 quired to activate the formaldehyde so that it at once poly- 

 merises to that required for the synthesis of the formaldehyde 

 itself does not suggest that the newly synthesised formaldehyde 

 is an active modification. It would seem that the activated 

 compound is formaldehyde which has been exposed to light 

 of wave-length 2gofi/ii, and no experimental work in the pre- 

 sent paper is at variance with this. 



The authors show that formhydroxamic acid is formed by 

 the action of activated formaldehyde on nitrate or nitrite 

 by passing carbon dioxide through aqueous solutions of 

 potassium nitrate or nitrite exposed to ultra-violet light, and 

 also by submitting solutions of potassium nitrite containing 

 formaldehyde to the same influence. Further, formhydroxamic 

 acid itself reacts with activated formaldehyde to give complex 



