24 THE EVOLUTION OF LIFE 
occurred only once or more in some remote geo- 
logical ages, as many are inclined to think; or 
whether it is a process that has been going on ever 
since it first began, all through the ages, and is one 
still continuing to occur at the present day. 
When it was said, a few pages back, that ‘no 
person possessing a fair amount of chemical and 
biological knowledge” now doubted that a natural 
origin of living matter had in the past occurred on 
this earth, it must not be forgotten that some years 
since (in 1871) Lord Kelvin, adopting a view 
previously expressed by another celebrated physicist 
(Helmholtz), threw doubt upon the subject by 
suggesting that life might have come to us on “the 
moss-grown fragments of another world.” This 
evasive and very improbable view seems now 
altogether beside the question, and as was pointed 
out by Sir George Stokes! would, of course, “‘ leave 
untouched the problem of the origin of life.” This 
eminent physicist added, “I need not dwell, how- 
ever, on the very formidable difficulties which stand 
in the way of any such hypothesis, for example, the 
intense superficial incandescence produced in a 
meteorite by its rapid passage through the air, for | 
do not conceive that the hypothesis was ever meant 
to be adopted.” 
Some astronomers, indeed, so far from doubting 
that Archebiosis originally occurred on the earth, go 
so far as to think that life of some sort is to be 
found even on other planets belonging to our own 
solar system. Thus, Dr H. H. Turner, Professor of 
1 “Lectures on Light,” 1892, p. 331. 
