146 



KNOWLEDGE & SCIENTIFIC NEWS. 



(July, 1905. 



The Nature of Life. 



By Geoffrey Martix, B.Sc. (Lond.). 



II. 



Now the temperature and pressure on the world's 

 surface have not always remained exactly the same as 

 they are at present. Indeed, it is probable that the further 

 we go back, the higher was the temperature conditions 

 which held upon the world's surface. Probably, in- 

 deed, at the earliest times, the world's surface was a 

 white hot fluid mass surrounded by vast masses of 

 vapour. Consequently, in very early times, if living 

 matter existed, its structure must have been quite 

 different to that which it has at present. And the 

 further we go back, the greater must have been the 

 difference between the structure it possessed then and 

 the structure it possesses now. For at ordinary tem- 

 peratures and pressures, living matter contained the 

 exact quantities of the necessary elements (namely, 

 cartx)n. hydrogen, nitrogen, oxygen, sulphur, and 

 phosphorus) to make its critical temperature of de- 

 composition coincide with the conditions which hold 

 upon the earth. .And as the temperature and pressure 

 of the world altered, the relative quantities of these ele- 

 ments entering into the structure of living matter would 

 also have to alter in order to make its critical tempera- 

 ture and pressure coincide with the new temperatures 

 and pressures. 



The higher the temperature and pressure, in general, 

 the greater would be the tendency to let heavier and 

 less volatile elements enter into its structure, and at the 

 highest temperatures and pressures, living matter, if 

 it existed at all, must have been composed out of alto- 

 gether different elements to those which at the present 

 time enter into its structure. 



I would, in fact, suggest that the structure of living 

 matter has, like most other things, undergone a con- 

 tinuous process of evolution (and is still undergoing it) 

 with the changing extern.il conditions, and that at the 

 time when the earth was a white hot fluid sea, life still 

 existed in a form quite different to that which it now 

 nossesses; that the chief elements entering into its 

 structure were at that time heavy non-metallic elements, 

 such as silicon, sulphur, phosphorus, and oxygen; 

 and that as the world gr.iduallv cooled, the heavier 

 clements were gradually eliminated and the lighter ele- 

 ments took their place by a natural process of circula- 

 tion, until finally the composition of living matter 

 assumed its present one. 



N'ow is there any element which could play at high 

 temperatures in living matter the part plaved therein 

 at ordinary temperatures by carbon? .Silicon is such 

 an element. .Silicon, like carbon, possesses a high and 

 constant valency, has a very considerable capacity for 

 self-combination, and is capable of giving rise to an 

 enormous number of very complex bodies— the silicates 

 and their derivatives— which well vie in complexity 

 with the most intricate carbon compounds. The 

 fundamental difference between the two sets of com- 

 pounds is essentially one of temperature, the carbon 

 compounds being at ordinary temperatures much nearer 

 thf^ir mcltmg and decomposing points than the silicates. 



Seemg that the temperature whereat carbon gives 

 rise to protoplasm is at a temperature at whirh most of 

 Its compounds with hydrogen, oxygen, and nitrogen 

 are (probably on account of thr-ir instability; spp 



the author's work, " Researches on the Affinities of 

 the Elements," pp. 120-123) '" a fluid or semi-fluid 

 state, we should expect that the most suitable tempera- 

 ture for silicon to give rise to an unstable compound 

 would be the temperature whereat the silicates are un- 

 stable and, therefore, in a fluid or semi-fluid state — 

 that is to say, at a white heat. Have we any evidence 

 to support the view that living matter did not start 

 originally with carbon, hydrogen, oxygen, and nitrogen 

 as its fundamental elements, but started with elements 

 of far higher atomic weights, such as silicon, phos- 

 phorus, sulpluir, ;in(l oxygen, of which only \esliges 

 now remain in the protoplasm? In this connection it 

 must be remembered that our evidence could be only 

 indirect. For such life might have flourished to an 

 enormous extent in the molten sea of siliceous matter 

 which covered the earth's surface in bygone ages, and 

 yet have left no traces of its existence behind; for when 

 such forms of life died, their bodies would but blend 

 again into the molten rock, in the same way that a 

 jelly-fish dies and blends again into the ocean of salt 

 water, without leaving a vestige behind to show that 

 it has been and gone. Except under exceptional cir- 

 cumstances, organised matter, when dead, very quickly 

 disintegrates. 



However, many remarkable siliceous minerals exist — 

 for example, the mineral " Asbestus " or mountain 

 leather — whose peculiar fibre-like structure may be due 

 to its previous organic nature in bygone ages. Again, 

 in some of the most rudimentary forms of organised 

 existence — for examples, the diatoms and sponges — 

 silica still remains in considerable quantities. 



Now it is clear that in consequence of the progressive 

 cooling of the earth, the range of temperature at which 

 silicon possesses the capacity for forming the central 

 element of living matter would soon be passed, and 

 hence its complexes would solidify out into stable 

 masses, thus causing all life to cease. 



But if carbon entered more and more fully into the 

 composition of living matter, and the silicon as steadily 

 solidified out as the cooling continued, the critical tem- 

 perature of decomposition (or temperature whereat life 

 is possible) would become progressively lower in pro- 

 portion as the amount of carbon in the organism in- 

 creased, and hence the cooling of the surrounding 

 medium, and the alteration in the living temperature 

 of the organism, would proceed together and keep pace 

 — the temperature of the organism lagging slightly be- 

 hind the falling temperature of the surrounding medium 

 — -as it actually does now in world life. The silicon 

 age would thus blend imperceptibly into the carbon age, 

 and when the modern thermal conditions were attained, 

 the carbon would long since have replaced completely 

 the silicon in living matter, and the last era of organic 

 existence would have been entered upon.. I believe 

 that silicon once completely replaced carbon in matter 

 living at a white heat, but that at ordinary temper.i- 

 tures it has been completely replaced by carbon, and 

 remains now merely in certain forms of life as an in- 

 active sediment solely because it can be put to a useful 

 purpose by imparting rigidity to the frame. In cases 

 where it serves no such purpose it has been already 

 completely eliminated; for example, in animal proto- 

 plasm only minute traces remain; on the other hand, in 

 grasses and diatoms very large quantities of silicon 

 still exist. 



Just as water, the mother liquid in which modern 

 protoplasm first throve, enters to a very large extent 

 into its composition; so also we should export thnt 



