3o8 LIFE : OUTLINES OF GENERAL BIOLOGY 



Before passing from the photosynthesis in Nature to Professor 

 Baly's artificial photosynthesis, we must emphasise the ecological 

 importance of the ordinary world process. In short then, {a) it is on 

 this activity of green plants that they, and the animal world from 

 them, dejxjnd directly or indirectly for sustenance; {h) the liberation 

 of oxygen as a by-product has been gradually— and this throughout 

 geologic time since verdure began in sea and on land— evolving a 

 breatliable atmosphere, needed even for plants themselves, and for 

 animals yet more; (c) the formation of carbon compounds has led 

 to the accumulation of the potential energy of coal-beds, lignites, 

 and peat-mosses: and as we consume these CO3 is returned to the 

 atmos[)here. Yet far more has been locked up, and mostly by animal 

 life, in static and practically irredeemable form, in the limestones 

 and chalk which bulk so largely in world geology. 



Baly's Artificial Photosynthesis. — Professor Baly, of Liver- 

 pool University, and his collaborators have been able to imitate (if 

 not in some measure also reproduce) the photosynthesis that occurs 

 in the green leaf. Water containing carbonic acid was subjected to 

 prolonged illumination by a mercury-vapour lamp (giving out light 

 with very short wave-lengths), and the result was the appearance 

 of formaldehyde (CHjO), which many botanical physiologists had 

 come to regard as the first or second carbon compound to be built 

 up in the leaf. With continued illumination of the solution vnth 

 light of somewhat longer wave-length, he obtained glucose, which 

 is one of the main products of natural photosynthesis. 



Still with the mercury-vapour lamp, Baly proceeded to induce 

 the formaldehyde to unite with nitrites, thus forming nitrogenous 

 carbon compounds; thus approaching the proteins which are 

 characteristic ol living matter. It will be noted that nitrites are 

 substances readily available in Nature, being produced for instance 

 when lightning fixes the nitrogen of the air in the form of nitrous 

 oxide, which is brought down by the rain in the form of nitrite of 

 ammonia. Chemical industry now does something closely analogoiis 

 in fixing the free nitrogen of the air by help of powerful electric 

 discharges, and thus obtains a basis for the manufacture of nitro- 

 genous fertilisers. 



Meeting the objection that we do not quite find the equivalent 

 of the mercury- vapour lamp in nature, Baly next devised a further 

 photosynthetic process, less artificial, since using ordinary* sunlight. 

 In the presence of certain "photo-catcfysts", that is to say coloured 

 substances which make the energy of the light more available, the 

 same substances were formed again. An encouraging result; yet to 

 which the previous objection reappears, against the use of an 

 artificial catalyst. Yet to this may be answered that chlorophyll as 

 an iron-containing pigment, may be, or may contain, the catalyst. 



These highly interesting experiments require to be confirmed and 



