NA TURE 



[May 7, 1908 



LETTERS TO THE EDITOR. 

 [The Editor docs tiot hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 JVo notice is taken of anonymous commwiications.] 



Life on Mars. 



If the canals of Mars are structures made by intelligent 

 beings, it is difficult to believe that these beings have not 

 at their disposal appliances both for construction and 

 survey. It is difficult to believe that some of these appli- 

 ances are not made of metal. If made of metal, it is 

 difficult to believe that the Martians do not use fire. There 

 is strong evidence that friction was the source of the dis- 

 covery of fire on the earth. But is it likely that fire would 

 be discovered by friction on a planet the barometrical 

 pressure of which is less than 4 inches of mercury, and 

 the still atmosphere of which is believed to be free from 

 thunderstorms and lightning flashes? 



The obvious, and I think adequate, criticism of such an 

 argument is that it is anthropomorphic. It interprets the 

 conditions of life on Mars too much in terms of human 

 experience. In the present state of our knowledge, may 

 not the same criticism be made of the assertion that life 

 on Mars is accompanied by an intelligence similar to our 

 own? On the earth, life without any high degree of 

 intelligence has been the rule. Life with a high degree of 

 intelligence has been the exception, an exception confined 

 to an insignificant fraction of the time during which 

 mundane life has existed. Is it safe, without very cogent 

 evidence, to assert that a similarly exceptional state of 

 things exists on Mars? Can no other possibilities be 

 suggested? 



To be told that life exists on Mars tells us but little of 

 its nature. It does not even tell us that living beings 

 exist. Perhaps on Mars there is only one living being, a 

 gigantic vegetable the branches or pseudopodia of which 

 embrace the planet like the arms of an octopus, suck 

 water from the melting polar snow^s, carry it to other 

 parts of the planet, and are visible to us as the Martian 

 canals. Lowell adduces the straightness of the canals as 

 a proof that they are artificial products of intelligent 

 beings. But they are certainly no straighter than the 

 somewhat similarly interlaced pseudopodia seen in certain 

 Heliozoa, Foraminifera, and Radiolaria. 



That this idea is not excluded by anything necessarily 

 inherent in the nature of living matter may be shown by 

 considering the conditions that must have accompanied the 

 origin of life, whether on the earth or on Mars. Paren- 

 thetically, it may be remarked that the existence of life 

 on Mars is not without bearing on the problem of the 

 origin of life on the earth, and Lowell's discovery may be 

 regarded as adding reason to the hope that has been ex- 

 pressed that some day life may be artificially produced in 

 our laboratories. 



It is impossible to believe that life originated directly 

 by a fortuitous concourse of atoms of the elements of 

 which living matter consists. Organic compounds must 

 first have come into existence as links between the living 

 and the not living. Some clues as to the nature of these 

 links possibly may be afforded by current researches on 

 the fixation of atmospheric nitrogen. We may surmise 

 that some stages in the evolution of living matter were 

 amino-acids, polypeptids, and proteids. The fact that 

 nowadays no such substances exist in natural water does 

 not disprove this supposition, for had such compounds 

 existed they must long ago have been destroyed by bacteria 

 and similar organisms. We may surmise that gradually 

 these primeval proteids became aggregated into larger 

 and larger molecular complexes until they existed as a 

 loose jelly of indefinite extent, that these complexes were 

 subjected to a slow oxidation, that, if we may accept 

 Pfluger's doctrine of the nature of respiration, these 

 molecular complexes, under the influence of oxidation, 

 acquired a certain molecular instability, but showed at 

 first no other vital character than the power of combining 

 with or assimilating other molecules of primeval proteid. 



NO. 2010, VOL. 78] 



However imperfect such a conception may be, there can 

 be no doubt that the process of the origination of life 

 was in the main a process of building up (one is tempted 

 to use the word polymerisation) of small simple aggregates 

 into larger and more complex aggregates. I can see no 

 reason for believing that there was anything in the nature 

 of this primitive living matter that would prevent this 

 process of aggregation from continuing Indefinitely. Or, 

 in other words, wc have no right to assert that there 

 could have been anything in the nature of the primitive 

 living matter itself to prevent it forming a scum of un- 

 limited extent on the water in which it existed. 



The fact that such indefinite growth either did not 

 occur, or, if it did occur, was only a transient stage in 

 evolution, may safely be ascribed to the effect of some 

 external forces or conditions of the environment. An 

 illustration may make this clear. Ice-crystals have the 

 property of aggregating together to form snow-flakes. 

 Owing to conditions and forces external to themselves, the 

 process of aggregation does not continue indefinitely, but 

 the snow-flakes cease to grow when they have reached a 

 certain size. Under another set of conditions, ice-crystals 

 mav not form snow-flakes at all, but may cover a large 

 extent of country in the form of hoar-frost. Similarly, the 

 primitive living matter on the earth, owing to the action 

 of some external forces or conditions, developed in the 

 form of separate individuals that we may compare to 

 snow-flakes. The possibility cannot be e-xcluded that on 

 Mars living matter developed in the form of a scum cover- 

 ing the seas of that planet, which scum would correspond 

 to the hoar-frost of our illustration. What external force 

 is there that would be likely to act on primitive living 

 matter on the earth, but not on Mars? Could it be the 

 action of tides and waves? 



.^11 I wish to assert is that it is possible and conceivable 

 for a single vegetable organism to come into existence on 

 a planet, and for it not to break up into separate in- 

 dividuals. In such a vegetable, parts unfitted for the 

 environment might perish and be assimilated by other 

 parts that were better adapted to the conditions that 

 existed. Thus it might possess a power of adaptation to 

 a changing environment, such ai must have occurred, for 

 example, in the drying up of the seas that once existed 

 on Mars. No one who believes in " the continuity of the 

 germ-plasm " will see any objection in the quasi- 

 immortality of such an organism. 



Another possibility may be suggested. Supposing, in 

 the course of many millions of years, the earth was to 

 follow the example of Mars and gradually to lose its water. 

 Should this happen, a stage would be reached in which a 

 few isolated lakes existed in the dried-up beds of the 

 oceans. Let us imagine what then might be seen by an 

 intelligent being on the planet" Venus who had " an eye 

 for planetary detail." Might he not see a system of 

 faintly shown lines stretching from lake to lake and to 

 the polar caps? Might they not show evidence of seasonal 

 change? And might he not then conclude that they were 

 canals made by beings of greater intelligence than his 

 own, though in reality they were only fronds of a gigantic 

 seaweed that had developed from the gigantic seaweeds 

 that at present exist in the Sargasso Sea? Is it not likely 

 that in the course of ages the fronds of such vegetables 

 would contract until they formed straight lines from oasis 

 to oasis, and so further the idea that their production was 

 due to intelligence? 



These ideas are obviously merely of the nature of sugges- 

 tions, and I wish expressly to disclaim holding any definite 

 opinion or belief as to the nature of the life on Mars. 

 Prof. Lowell has measured the rate of flow of water in 

 some of the Martian canals. Is this rate the " economical 

 rate " for the flow of water along an open canal, or does 

 it agree better with the economical rate, if the phrase is 

 applicable, for the flow of w'ater along pipes of a vegetable 

 organism, where presumably the loss from percolation and 

 evaporation would be trivial? 



Mv position is that one may admit that Prof. Lowell's 

 brilliant researches prove the existence of life on Mars, and 

 still ask from him further evidence before we are convinced 

 that that life is intelligent. E. H. H.4NKIN. 



Agra, India. 



