262 THE MAINTENANCE OF THE INDIVIDUAL 



is a poison, it is probably changed into sugar so rapidly that at no 

 time is there much present in the cells of the leaf. The last part of 

 this process, that of changing the formaldehyde to sugar, seems to be 

 brought about by the action of the two chlorophylls, A and B. One 

 recent writer, Gordon, > has given the following suggestive formula: 



6 C55H70O6N4Mg + 6 H2O = 6 C55H7205N4Mg + 602 

 (Chlorophyll B) (Chlorophyll A) 



6 C55H7205N4Mg + 6 CO2 = 6 C,r,H7o06N,Mg + CeHisOs 



(Chlorophyll A) (Chlorophyll B) (sugar) 



To the amateur chemist this means very little, but it suggests the 

 double action of the two chlorophylls in the formation of sugar. 

 All we really know is that sugar is first formed in the green leaf and 

 that later this is changed to starch and stored in that form in various 

 parts of the plant. 



Of the manufacture of foods other than sugar very little is known. 

 There are tiny droplets of fat in the vacuoles inside the chloroplasts. 

 We know that fats can be synthesized out of carbohydrates by 

 animals. Therefore, a similar process may take place in plants. 

 Fatty tissue is undoubtedly manufactured out of the carbon, oxygen, 

 and hydrogen contained in the sugar molecule. Probably a like 

 situation exists in the chloroplasts of the leaves, although we do not 

 know just how this process takes place. 



Proteins are even more complex than carbohydrates and fats. 

 Their molecule contains nitrogen and a number of mineral salts, 

 in addition to carbon, oxygen, and hydrogen. Protein foods are 

 found not only in leaves, but in most of the storage organs of the plant. 

 Apparently proteins can be synthesized out of the sugar plus the 

 elements nitrogen, sulphur, and phosphorus, wiiich combine with 

 the carbon, oxygen, and hydrogen of the glucose. Proteins are 

 probably manufactured in other cells than those containing chloro- 

 phyll, wherever .starches, sugar, and the essential salts are found, 

 although light does not seem to be a necessary factor in the process. 

 Proteins are undoubtedly used in any of the cells of the plant, just as 

 they are in animal cells, for the making of protoplasm, since the plant 

 is a living organism composed of cell units each of which is doing a 

 common work for the plant as a whole. 



1 Gordon, R. B. : " Suggested Equation for the Photo-synthesis, Action." Ohio Journal of 

 Science, 29: 131, 1929. 



