TRANSACTIONS OF SECTION B. 827 



as profound as the absolute origin of life itself. The two phenomena are intimately 

 connected, for, as we have seen, these symmetric compounds make their appearance 

 with life, and are inseparable from it. 



How, for example, could Isevo-rotatory protein (or whatever the first asymmetric 

 compound may have been) be spontaneously generated in a world of symmetric 

 matter and of forces which are either symmetric or, if asymmetric, are asymmetric 

 in two opposite senses ? What mechanism could account for such selective pro- 

 duction ? Or if, on the other hand, we suppose that dextro- and lasvo-protein were 

 simultaneously formed, what conditions of environment existing in such a world 

 could account for the survival of the one form and the disappearance of the other ? 

 Natiu-al selection leaves us in the lurch here ; for selective consumption is, under 

 these conditions, as inconceivable as selective production. 



No fortuitous concourse of atoms, even with all eternity for them to clash and 

 combine in, could compass this feat of the formation of the first optically active 

 organic compound. Coincidence is excluded, and every purely mechanical explana- 

 tion of the phenomenon must necessarily fail. 



I see no escape from the conclusion that, at the moment when life first arose, a 

 directive force came into play — a force of precisely the same character as that 

 ■which enables the intelligent operator, by the exercise of his Will, to select one 

 crystallised enantiomorph and reject its asymmetric opposite. 



1 would emphasise the fact that the operation of a directive force of this nature 

 does not involve a violation of the law of the conservation of energy. Enantio- 

 morphs have the same heat of formation ; the heat of transformation of one form 

 into the other is nil. Whether, therefore, one enantiomorph alone is formed, or 

 its optical opposite alone, or a mixture of both, the energy required per unit weight 

 of substance is the same. There will be no dishonoured drafts on the unalterable 

 fund of energ3^ 



The interest of the phenomena of molecular asymmetry from the point of 

 view of the biologist lies in the fact that they reduce to its simplest issues the 

 question of the possibility or impossibility of living matter originating from dead 

 matter by a purely mechanical process. They reduce it to a question of solid 

 geometry and elementary dynamics ; and therefore, if the attempted mechanical 

 explanation leads to a reductio ad absrirdum, this ought to be of a correspondingly 

 simple and convincing character. Let us see how far this is the case. 



life is a phenomenon of bewildering complexity. But in discussing the problem 

 of the origin of life this complexity cuts two ways. Whilst, on the one hand, it 

 is appealed to by one set of disputants as an argument against the mechanical 

 theory, on the other it affords shelter for the most unproved statements of their 

 opponents. I will take a concrete instance from the writings of an upholder of the 

 mechanical theory of the origin of life, the late Professor W. K. Clifford. He 

 says : 



' Those persons who believe that living matter, such as protein, arises out of 

 non-living matter in the sea, suppose that it is formed like all other chemical com- 

 pounds. That is to say, it originates in a coincidence, and is preserved by natural 

 selection. . . . The coincidence involved in the formation of a molecule so 

 complex as to be called living, must be, so far as we can make out, a very elaborate 

 coincidence. But how often does it happen in a cubic mile of sea-water P Per- 

 haps once a week ; perhaps once in many centuries ; perhaps, also, many million 

 times a day. From this living molecule to a speck of protoplasm visible in the 

 microscope is a very far cry; involving, it may be, a thousand years or so of 

 evolution.' 



It was easy for Clifford to write thus concerning life itself, for it was difficult 

 for any one to contradict him. But had he been asked whether any mechanical 

 (symmetric) coincidence would suffice to convert an infinitely great number of 

 molecules of the type shown in fig. 3 into that shown in (say) fig. 1, to the exclu- 

 sion of that shown in fig. 2 ; or whether, given a mixture, in equal proportions, of 

 molecules of the types shown in figs. 1 and 2, any mechanical (symmetric) condi- 

 tions of environment would bring about the destruction of one kind and the 



