52 TliANSACTIONS AND PROCKKDTNGS OF THE [Sess. Lxv. 



living substance of the cc41 ; that is to say, a contact 

 action takes place, of the nature of a continual miracle, 

 whereby the touch of the living matter raises the dead 

 matter to life. 



Biomolecular IJevelojmient. — Just as in the case of the 

 molecule of methyl-ethyl-ketone, so the biomolecule passes 

 through a series of " phases of biomolecular development." 

 Starting from its origin by fission from a pre-existing 

 biomolecule, it goes on undergoing successive transforma- 

 tions up to the phase of cUdouUement, when it splits into 

 two daughter molecules. This biomolecular development 

 is expressed in the diagram — 



a . . b . . c . . d . . M = a + a 



Here a represents the original molecule, and b, c, d the 

 successive phases of constitution of the biomolecule during its 

 transformation into M, when dddouhlement occurs. When 

 the resulting daughter molecules, a a, are identical to the 

 first a, and regenerate it, the development is mitogenetic, and 

 one biomolecular development' completes the " evolutionary 

 biomolecular cycle," and multiplication and reproduction are 

 simultaneous and concomitant phenomena. " Although the 

 simplest imaginable, autogenetic development is neither the 

 easiest nor commonest," because not only has the number of 

 atoms to be doubled, but the atoms have to be arranged so 

 that when doubling occurs each daughter molecule may 

 have its atoms arranged exactly as in the mother molecule, 

 so as to reproduce it in every respect Without this orien- 

 tation, which is the efficient cause of doubling, metameric 

 compounds would result. The greater the complexity of 

 the molecule, the greater the difficulty in the way of 

 autogenetic development. " When the biomolecule is very 

 complicated, the assimilatory reactions, also, will be very 

 complicated and very numerous, and, as the number of 

 atoms to be doubled is large, the nutritive substances also 

 mast be sufficiently complex to supply the biomolecule 

 with the complex atomic groups necessary for its develop- 

 ment." Hence the rarity of this mode of development in 

 nature. It occurs only among a few of the simplest 

 organisms — the bacteria, e.g. ; and hence the necessary 

 complex nature of the food of many of these organisms. 



