June, 1905.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



TKe Nature of Life. 



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



I. 



[This interesting paper, by Mr. Martin, opens up some new 

 conceptions regarding the nature and origin of life. 



In the first part the author commences by explaining how 

 all chemical compounds decompose at a certain critical tem- 

 perature and pressure, and how the number and kind of atoms 

 m the molecule decide the degree of temperature. He then 

 discusses what would be the composition and properties of a 

 substance whose critical temperature and pressure coincide 

 with those now prevailing on the earth's surface, and becomes 

 to the conclusion that living protoplasm possesses in every re- 

 spect the properties of such a compound. He then develops 

 this idea. Some parts of the protoplasm decompose some- 

 what more rapidly than other parts, and, corresponding more 

 sensitively to certain influences, thus develop into different 

 organs. 



In the second part (to be published next month), it is suggested 

 that since the temperature of the world's surface wasiu tormer 

 times very difi'erent to that which now prevails, the modern 

 protoplasm is simply the product of evolution of older kinds 

 of protoplasm, living at high temperatures, in which heavier 

 elements, such as silicon, phosphorus, sulphur, &c., replaced the 

 lighter elements which now principally compose it. 



In a third part, future developments are discussed. — Ed.] 



If we place a given chemical compound (say CaC03) 

 in a closed cylinder and subject it to a continually in- 

 creasing temperature, keeping the pressure constant 

 by means of the piston, then at a certain temperature 

 range the compound begins to decompose. If, now, 

 we increase the pressure sufficiently, the decomposition 

 ceases and the substance can now bear a higher tem- 

 perature than before without decomposing. Proceed- 

 ing in this way, it is obvious from the finite nature of 

 the mass of the atoms, and from the limited intensity 

 of the forces holding them together in the molecule, 

 that ultimately at some definite temperature the ex- 

 ternal forces tending to drive the atoms apart will 

 become equal to the maximum internal forces that the 

 atoms can exert on each other in the molecule. It is, 

 therefore, obvious that above a certain definite tem- 

 perature, depending upon the nature of the molecule, 

 no pressure, however great, can -prevent the substance jrom 

 completely decomposing. This temperature and pressure, 

 above which a compound is incapable of existing, we 

 will call the critical temperature and pressure of decom- 

 position of the compound. 



The critical temperature of decomposition v.ould, 

 therefore, be completely analogous to the critical tem- 

 perature of liquefaction of a compound — only in the 

 latter case we are dealing with the temperature whereat 

 a certain molecular condition of existence disappears; 

 and in the former case with the temperature whereat 

 a certain atomic condition of existence disappears. 



Since atoms are a very much more finely divided 

 form of matter than molecules, it is clear that the criti- 

 cal temperature of decomposition of a compound must 

 be a very much sharper and clear-cut constant than its 

 critical temperature of liquefaction. 



The critical temperature and pressure of decomposi- 

 tion of even very unstable compounds is usually very 

 high. For example, although AUCI3 is almost com- 

 pletely decomposed at about 200°, yet Rose's experi- 

 ments show* that it is capable of existing in traces at 

 very high temperatures indeed. Cyanogen, ozone, and 

 • /■). Chem. Soc. (1895) 67. 8S1. 



the oxides of nitrogen, although very unstable at 

 ordinary temperatures, seem capable of existing at ex- 

 cessively hign temperatures. 



In general, the smaller the number of atoms in the 

 molecule of a compound, the higher is its critical tem- 

 perature of decomposition; whereas the greater the 

 number of atoms, the lower the critical temperature. 

 1 he reason of this is, of course, due to the general fact 

 that the more atoms there are added on to a molecule, 

 the feebler is the intensity of the forces holding the 

 atoms together in the molecule — as is evident from the 

 general observation that the more complex a compound 

 is, the more easily decomposable it is. 



If, now, by some means or other we proceed to 

 steadily add on atoms to a molecule so as to make it 

 more and more complex, we steadily lower its critical 

 temperature of decomposition. And by adding on a 

 suitable number and kind of atoms, we could reduce 

 the critical temperature and pressure of the compound 

 until they coincided with the normal temperatures and 

 pressures ivhich hold upon the earth's surface. 



Such a compound would be possessed of an extra- 

 ordinary sensitiveness to external influences on ac- 

 count of the sharpness of the constants called above 

 the critical temperature and pressure of the compound. 

 A slight increase of temperature, or a slight decrease of 

 pressure, would serve to throw it into a condition of 

 rapid chemical decomposition; whereas a slight in- 

 crease of pressure and decrease of temperature would 

 cause the substance to suddenly cease to decompose; 

 and even did we maintain the external temperature and 

 pressure exactly at the critical temperature and pressure 

 of the compound, nevertheless, the external impulses 

 which are continuously pervading all space in the 

 neighbourhood of the solar system, beating inter- 

 mittently upon the sensitive substance, would alone 

 be sufficient to throw it into a series of rapidly 

 alternating states of decomposition and repose. 



In order to generate such a complex compound, we 

 must first take as the central atom an atom capable of 

 exerting a high grade of valence, and possessing a 

 well-developed power of self-combination. The high 

 valency grade of the central atom is necessary in order 

 that we may be able to add on to it atoms of different 

 natures so as to regulate precisely the stability of the 

 resulting compound; and the power of self-combination 

 is advisable in order that the molecule may be of the- 

 necessary grade of complexity, so as to reduce its 

 critical temperature and pressure of decomposition 

 exactly to the temperature and pressure which hold 

 upon the earth's surface. The atoms added on to the 

 central atom must possess a small but perceptible 

 affinity for the atom and for themselves. 



What known elements, therefore, would be most 

 suitable to enter into the structure of such a compound? 

 A study of the elements will convince the reader that 

 the element of high valency grade which possesses the 

 power of self-combination (and, therefore, the possi- 

 bility of generating complex compounds) most highly 

 developed is carbon; and the five elements most 

 abundant upon the earth, which possess a small but 

 quite definite mutual affinity for carbon and for them- 

 selves, are hydrogen, oxygen, and nitrogen, and in a 

 lesser degree sulphur and phosphorus. 



We should expect, therefore, to find such a complex 

 compound to be composed chiefly out of carbon, 

 hydrogen, oxygen, nitrogen, and containing small 

 amounts of sulphur and phosphorus. Our conclusion 

 is confirmed when we come to survey the nature of the 



