THE PHOTOSYNTHETIC PROCESS 59 



1. Water may split off producing the phloroglucin : 



XT 



H 



I 

 C 



/\ 



OH— C C— OH 



H— C C— H 



v / 



V 



C 



OH 



2. The ring may split forming a chain compound, — the glucose. 



3. The same thing may happen forming fructose. 



4. The compound may " settle down" and become inactive 

 forming inosite. The plant makes all of these at once but in 

 vitro no fructose is found because it is very unstable and is de- 

 stroyed as fast as formed. Furthermore when a solution of carbon 

 dioxide was exposed to ultra-violet light, formaldehyde was formed 

 and then sugars. 



In these experiments, catalysts of various sorts are included 

 in the tubes to hasten the chemical reactions, and it was Baly's 

 experience that the color of the catalyst was important. Thus 

 when the catalyst had a green surface (NiC0 3 ), there were better 

 results than when a white catalyst was used, but pink (C0CO3) 

 was as efficient as green. It is his belief that chlorophyll A com- 

 bines with carbon dioxide to form chlorophyll B and formalde- 

 hyde. The chlorophyll B then reacts with carotin and water to 

 form A and xanthophyll, which in turn is then reduced by some 

 enzyme to re-form the carotin and release oxygen, after which 

 the formaldehyde is polymerized to form a hexose sugar. 



C55H 72 05N 4 Mg+C02 = C^H 7 o0 6 N4Mg+CH 2 



(chlor. A) (chlor. B) 



C66H70O6N4Mg + C40H56 + H2O = C65H72O5N 4 Mg + C40H56O2 



(carotin) (xanthophyll) 



C40H 560 2 —> v>4oH 56 + 02 • 



This scheme has the further advantages of being simple and of 

 explaining the presence of all the materials found in close associa- 

 tion with chlorophyll. The chief objection to all the work of Baly 

 is that it has been done entirely in vitro, and, as Barton- Wright 

 has phrased the matter, "it is somewhat absurd to compare the 



