September 6, 1912] 



SCIENCE 



297 



of non-living matter — life became estab- 

 lished? Is there any valid reason to eon- 

 elude that at some previous period of its 

 history our earth was more favorably cir- 

 cumstanced for the production of life than 

 it is now? I have vainly sought for such 

 reason, and if none be forthcoming the con- 

 clusion forces itself upon us that the evolu- 

 tion of non-living into living substance has 

 happened more than once — and we can be 

 by no means sure that it may not be hap- 

 pening still. 



It is true that up to the present there is 

 no evidence of such happening: no process 

 of transition has hitherto been observed. 

 But on the other hand, is it not equally true 

 that the kind of evidence which would be 

 of any real value in determining this ques- 

 tion has not hitherto been looked for ? We 

 may be certain that if life is being pro- 

 duced from non-living substance it will be 

 life of a far simpler character than any 

 that has yet been observed — in material 

 which we shall be uncertain whether to call 

 animate or inanimate, even if we are able 

 to detect it at all, and which we may not be 

 able to visualize physically even after we 

 have become convinced of its existence. 

 But we can look with the mind's eye and 

 follow in imagination the transformation 

 which non-living matter may have under- 

 gone and may still be undergoing to pro- 

 duce living substance. No principle of evo- 

 lution is better founded than that insisted 

 upon by Sir Charles Lyell, justly termed 

 by Huxley "the greatest geologist of his 

 time, ' ' that we must interpret the past his- 

 tory of our globe by the present; that we 

 must seek for an explanation of what has 

 happened by the study of what is happen- 

 ing; that, given similar circumstances, 

 what has occurred at one time will probably 

 occur at another. The process of evolution 

 is universal. The inorganic materials of the 

 globe are continually undergoing transition. 



New chemical combinations are constantly 

 being formed and old ones broken up ; new 

 elements are making their appearance and 

 old elements disappearing. Well may we ask 

 ourselves why the production of living 

 matter alone should be subject to other 

 laws than those which have produced, and 

 are producing, the various forms of non- 

 living matter ; why what has happened may 

 not happen? If living matter has been 

 evolved from lifeless in the past, we are 

 justified in accepting the conclusion that 

 its evolution is possible in the present and 

 in the future. Indeed, we are not only 

 justified in accepting this conclusion, we 

 are forced to accept it. When or where 

 such change from non-living to living 

 matter may first have occurred, when or 

 where it may have continued, when or 

 where it may still be occurring, are prob- 

 lems as difficult as they are interesting, but 

 we have no right to assume that they are 

 insoluble. 



Since living matter always contains 

 water as its most abundant constituent, 

 and since the first living organisms recog- 

 nizable as such in the geological series were 

 aquatic, it has generally been assumed that 

 life must first have made its appearance in 

 the depths of the ocean. Is it, however, 

 certain that the assumption that life origi- 

 nated in the sea is correct? Is not the 

 land-surface of our globe quite as likely to 

 have been the nidus for the evolutionary 

 transformation of non-living into living 

 material as the waters which surround it? 

 Within this soil almost any chemical trans- 

 formation may occur; it is subjected much 

 more than matters dissolved in sea-water 

 to those fluctuations of moisture, tempera- 

 ture, electricity, and luminosity which are 

 potent in producing chemical changes. 

 But whether life, in the form of a simple 

 slimy colloid, originated in the depths of 

 the sea or on the surface of the land, it 



