THE PRODUCTS OF PHOTOSYNTHESIS 223 



version product of the carbohydrates. Both views have been defended 

 by various investigators, but it is evident that considerably more work 

 will be necessary in order to determine the nature of the chemical re- 

 actions involved."® 



Meyer/-" on the basis of microchemical examination comes to the 

 conclusion that the oil droplets which appear in the chloroplasts of Vaiuhere 

 are a direct product of photosynthesis. The accumulation of the oil, accord- 

 ing to Meyer, depends upon the rate at which it moves into the cytoplasm 

 and possibly also on its consumption in respiration. He considers that 

 the oil is not a fat, though the evidence on this point does not seem to 

 be altogether clear from the chemical viewpoint. 



There are many plants the photosynthetic activity of which has not 

 been studied at all and others in which this process has been followed 

 only in a very crude manner. Undoubtedly many very important observa- 

 tions regarding the process could be made by using plants in which the 

 course of the photosynthetic reactions is apparently different from those 

 usually studied. The diatoms, which also form oil, and many of the 

 plants of the sea offer very interesting material for further study. 



The formation of hydrogen peroxide has for theoretical reasons been 

 a matter of much interest. The role of hydrogen peroxide in the oxida- 

 tive processes of the plant in accordance with the theories of Traube has 

 received a great deal of attention, though, largely through the studies 

 of Pfeffer, the presence of hydrogen peroxide in the living cell seemed 

 unlikely. In the theoretical treatments of the photosynthetic process also, 

 the intermediate formation of hydrogen peroxide has been assumed, as, 

 for example, Nef ^-' suggested that the reduction of carbonic acid to 

 formaldehyde was brought about by the dissociation of the carbonic acid : 



/ 



OC(OH)o > OC -f H3O2 > OCH2 + O2. 



\ 



Thunberg^" ^^^ ^\^q formulated a theory in which hydrogen peroxide 

 should reduce the carb'onic acid ; though it has since been found that the 

 theory is based upon an erroneous observation. 



Kleinstiick ^'^^ reported that hydrogen peroxide could be detected as a 

 result of the photosynthetic activity of Elodea. His experiments were 

 repeated by Molisch with negative results. Tanaka, on the other hand, 

 has found that ChlareUa in Knop's solution free of phosphate, when 



"'Briosi, Bot. Zeitg., 31, 529 (1873). HoUe, Flora, 35, 113, 154, 161, 184 

 (1877). Godlewski, ibid., 35, 215 (1877). Schimper, Jahrb. zmss. Bot., 16, 178 

 / logs') 



-"Meyer, Ber. bot. Gcs.. 35, 586 (1917) ; 36. 235 (1918). 

 Nef, Ann. Cliem., 357, 253 (1907). . , 



'Thunberg, Zcit. phys. Chem., 106, 305 (1923). Weigert, ibid., 106, 313 (1923). 

 Bach and Monosson, C. .-i., 18, 2910 (1924). ^ „■ , 7., ,oc 



"^Kleinstiick, Ber. chem. Ges., 51, 108 (1918). Molisch, Biochem. Zett., 125, 

 257 (1921). Tanaka, ibid.. 157, 433 (1925). 





