THE ORIGIN OF LIFE 171 



messengers of life — that germs of life had been 

 brought to earth tucked away in the interstices of 

 meteoric stones. At first the objection was made 

 that any living germs in the pores of the meteor 

 would be destroyed by the great heat generated as 

 the meteor flashed through the earth's atmosphere, 

 but the objection is not valid, since it has been 

 found that only the surface of the meteor is fused, 

 and that its interior is comparatively cool. Granted 

 that life began at an earlier date on another planet, 

 granted that meteors are fragments of planets, it is 

 quite possible that life was brought to earth in the 

 womb of a meteor. But even if we accept this 

 theory of the origin of life, we only shift the 

 problem to another planet. 



Kelvin held that " Dead matter cannot become 

 living without coming under the influence of 

 matter previously alive. This seems to me as 

 sure a teaching of science as the law of gravita- 

 tion." Since, then, it was quite evident that hfe 

 had at one time been unknown on the world, it 

 followed that it could never have appeared unless 

 created by a miracle or imported. Kelvin chose 

 the alternative of importation, and, in a presidential 

 address to the British Association in Edinburgh in 

 1 87 1, he declared his creed thus : — 



" When two great masses come into collision in 

 space, it is certain that a large part of each is 



