60 TKANSAGTIONS AND I'UOCEEDING.S OF THK [Sess. Lxv. 



" The amylogenic function is independent of tlie chloro- 

 phyll function, that is, it can go on quite well without it. 

 The atomic linkage characteristic of starchy substances is 

 dependent on the structure of the biomolecules and the 

 chemical change resulting from their processes of assimila- 

 tion, no matter how the carbon be assimilated. It follows 

 that non-chlorophyllous organisms, as amylogenic bacteria, 

 may nevertheless form starch, while other organisms 

 possessed of chlorophyll or of bacterio-purpurin have not, 

 in spite of the presence of these substances, the power to 

 form carbohydrates." 



We may point out that these results, arrived at by 

 theoretical considerations, coincide pretty closely with the 

 views of modern botanists, as determined practically and 

 experimentally. We know, for example, that leukoplasts, 

 which are are non-chlorophyllous plastids, form starch. 

 Further, Bohra ("Bot. Zeit.," 1883) proved, experimentally, 

 that chloroplasts formed starch in the dark when artificially 

 supplied with sugar. Again, from the researches of Ewart 

 ("Jour. Linn. Soc," 1897), we know that etiolated chloro- 

 plasts, without the slightest trace of chlorophyll, show a 

 faint power of carbon-assimilation. Further, as showing 

 that it is not a contact action, Engelmann ( " Bot. Zeit.," 

 1881), by the bacterium method, showed that the actual 

 assimilation of the carbon dioxide probably takes place 

 in the plastid. 



The discussion of the food conditions necessary for the 

 artificial life of the chemical molecule is instructive, and 

 suggests interesting considerations as to the role played by 

 certain food elements in the nutrition of plants. 



The food elements of the biomolecule are classified as 

 follows : — 



(1) The Indispensable. — These that are actual constituent 

 elements of the molecules. 



(2) Necessary. — These are part constituent of the mole- 

 cule only temporarily, their presence being necessary for 

 the completion of subsequent reactions. 



(3) Useful. — Elements which never enter into the 

 molecule, nevertheless they are useful and necessary for 

 assimilation, inasmuch as they provoke, by their affinity, 

 chemical changes in the molecule. 



