58 TRANSACTIONS AND PKOCEEDINGS OF THE [Sess. Lxv. 



biomoleciile complete its development, so as ultimately to 

 be doubled into two new molecules ? It is pointed out 

 that the loss of some atoms " does not always indicate the 

 destruction of a biomolecule, because this same loss may be 

 the cause of a molecular reconstitution or augmentation, 

 simultaneous or subsequent." The reaction, previously 

 referred to, of acetic acid with isocyanate of ethyl, is cited 

 in illustration. Here the acetic acid loses one atom of 

 carbon, but, at the same time, in its transformation it has 

 added three new atoms of carbon from the molecule of 

 ethyl-isocyanate, and has more than made good its loss. 



On similar lines, an explanation is afforded of the 

 function of the chloroplasts and of starch formation. The 

 error is pointed out of regarding these two processes, 

 viz. assimilation (in the narrow sense as used by botanists 

 — assimilation of carbon from the carbon dioxide of the 

 air, and emission of oxygen) and starch formation as 

 indissolubly bound together. They are independent of 

 each other, although they may coexist in the same mole- 

 cule. If the two functions were in absolute connection, 

 the action of the chloroplasts would be of the nature of 

 a contact action to induce the decomposition of carbon 

 dioxide, the carbon of which would unite with the water 

 of the medium, and would form starch or some other 

 carbohydrate, and the molecules of the plastid would play 

 no active role in the production. If chlorophyll and starch 

 formation were thus indissolubly bound together, how 

 explain the formation of starch by non-chlorophyllous 

 organisms as the amylogenic bacteria ? and, on the other 

 hand, why do certain bacteria possessed of chlorophyll or 

 of bacterio-purpurin form no starch ? The error is in 

 linking together two processes which, in reality, can go 

 on quite independently. 



" Starchy substances are the products of secretion of 

 biomolecules, that is, the molecules which constitute them 

 are atomic groups, derived in part or m toto from the 

 biomolecules in the course of certain assimilatory reactions. 

 We have no right to affirm that the formation of starchy 

 substances takes place entirely outside the biomolecules. 

 Why should it not be admitted that these atomic groups 

 are constituted, in part at least in the interior of the 



