80 SECTIONAL ADDRESSES. 



held as to where hfe in the world had its origin, but no one questions 

 that it began in close connection with water. That it began in the 

 sea, where the necessary elements were present in appropriate concen- 

 trations and in an ionised state, is an idea which appeals to many with 

 increasing force the more closely it is examined. This view has been 

 developed recently by Church^ in his memoir on ' The Building of an 

 Autotrophic Flagellate,' in which he boldly attempts to trace the pro- 

 gression from the inorganic elements present in sea-water to the uni- 

 cellular flagellate in the plankton phase, floating freely in the water. 

 The autotrophic flagellate, manufacturing its own food, he regards as 

 the starting-point from which all other organisms, both plants and 

 animals, have sprung. To understand the first step in this progression, 

 the passage from the dead inorganic to the living organic remains, as it 

 has always been, one of the great goals of science, not of biological 

 science alone, but of all science. Recent research has, I think, thrown 

 much light on the fundamental problems involved. In a paper pub- 

 lished last year, Baly, Heilbron, and Barker,* extending and correcting 

 previous work by Benjamin Moore and Webster,^ have shown that 

 light of very short wave-length (X= 200 w-l), obtained from a mercury- 

 vapour lamp, acting upon water and carbon dioxide alone, is capable 

 of producing formaldehyde, with liberation of free oxygen. Light of 

 a somewhat longer wave-length ( X = 290 [ly-) causes the molecules of 

 formaldehyde to unite or polymerise to form simple sugars, six mole- 

 cules of formaldehyde, for example, uniting to form hexose. The 

 arresting fact brought out in these researches is that the reactions take 

 place, under the influence of light of appropriate wave-lengths, without 

 the help of any catalyst, either organic or inorganic. Where a source 

 of light is used which furnishes rays of many wave-lengths, the simple 

 reaction of the formation of formaldehyde is masked by the immediate 

 condensation of the formaldehyde to sugar, but this formation of sugar 

 can be prevented by adding to the solution a substance which absorbs 

 the longer wave-lengths, so that only the short ones which produce 

 formaldehyde are able to act. 



When the formation of sugars is postulated, the introduction of 

 nitrogen into the organic molecule offers little theoretical difficulty ; for 

 not only has Moore'' shown that nitrates are converted into the more 

 chemically active nitrites under the influence of light of short wave- 

 length, but he maintains that marine algee, as well as other green plants, 

 can under the same influence assimilate free nitrogen from the air. 

 Baly^ also has succeeded in bringing about the union of nitrites with 

 active formaldehyde in ordinary test-tubes by subjecting the mixture 

 to the light of a quartz-mercury lamp. 



•■' B'iological Memoirs, I. Oxford, 1919. 



* Journ. Chem. Soc, London, vols. 119 and 120, 1921, p. 1025. Nature, 

 vol. 109, 1922, p. 344. 



" Proc. Boy. Soc. B.. vol. 87, p. 163 (1913), p. 556 (1914); vol. 90, p. 168 

 (1918). 



G Proc. Boy. Soc. B., vol. 90, p. 158 (1918); vol. 92, p. 51 (1921). 



■ Balv. Heilbron and Hudson, Journ. Chem. Soc. London, vols. 121 and 

 122, 1922, p. 1078. 



