54 TRANSACTIONS AND PROCEEDINGS OF THE [Sess. Lxv. 



return, after a vital period more or less long, to the 

 starting-point — never perishing, immortal; the latter never 

 returning to the starting-point — mortal, and destined to 

 perish. Somatic biomolecules, although powerless for 

 reproduction, nevertheless may assimilate and live, and 

 give origin to other different molecules, and ultimately to 

 molecules like themselves. 



The results of the two last methods of development, as 

 seen in organisms, are next described. An organism con- 

 stituted of biomolecules with homogenetic development 

 grows during its vital period by the duplication of its 

 molecules resulting from each dMouUement. At the 

 completion of its life cycle, reproduction will ensue ; there 

 will be no somatic biomolecules, and the whole body of 

 the organism will take part in the reproduction, which will 

 not be a simple fission but a true sporulation. On the 

 contrary, an organism composed of biomolecules with 

 heterogenetic development at reproduction will be com- 

 posed of two kinds of biomolecules — the genetic, which 

 will regenerate the primitive biomolecules ; and the somatic, 

 taking no active part in reproduction, but which will 

 constitute the " soma " of the organism. 



Heterogenetic development is the most frequent in 

 nature, because it is easiest of accomplishment ; it lies 

 at the root, and is the prime cause, of ontogenetic 

 differentiation. 



For the accomplishment of homogenetic and hetero- 

 genetic developments a series of several biomolecular 

 developments is necessary to allow of assimilation, so 

 that the number of atoms may be gradually doubled, 

 and, more particularly, to allow of the gradual orientation 

 of the atoms ; so that when d4douhlemcnt occurs the new 

 molecules may have their atoms linked together in chains 

 similar to those in the primary molecule. The latter is 

 the greatest difficulty, and increases with the size and 

 complexity of the molecules. Thus there are to be 

 recognised " phases of biomolecular preparation " in the 

 evolutionary cycle, during which assimilation goes on, 

 extending from the first to the penultimate development; 

 and " phases of maturation," including the final develop- 

 ment, which ends in reproduction. The more complex the 



