288 Proceedings of the Royal Physical Society. 



of the earth. The problem which now confronts us is to 

 determine if the chain of organic life can be carried back 

 into the physical and chemical phenomena of the inorganic 

 kingdom. It is well known that the food of plants consists 

 almost entirely of inorganic compounds, i.e., water, carbonic 

 acid, ammonia, together with some minute quantities of 

 mineral matter. On the other hand, the food of animals 

 must contain matter which is the product of some other 

 living organism. In view of this intimate relationship 

 between the recognised phenomena of the animal, vegetable, 

 and mineral kingdoms, one would suppose prima facie that 

 there was little to be bridged over in the transition between 

 the inorganic and organic worlds ; but yet, according to the 

 most philosophical minds of the present age, they are separ- 

 ated by an impassable gulf. No biologist has ever yet 

 succeeded in showing experimentally that life can be gener- 

 ated from inorganic materials alone. The law enunciated by 

 Harvey — omne vivum ex ovo — is absolutely true so far as 

 the higher animals are concerned; and if it be slightly 

 amplified so as to read omne vivum ex vivo — thus covering 

 reproduction by gemmiparous and fissiparous processes — it 

 is true for all living things. Hence it follows that, if this 

 globe were completely sterilised and subsequently replaced 

 in its present environment, life would not again reappear on 

 its surface, unless its germs were imported from some external 

 source. So strongly had this view impressed Lord Kelvin, 

 that in 1871, in his address as President of the British 

 Association, then held in Edinburgh, he could offer no better 

 explanation of the origin of life on this earth than that 

 it was an importation " through moss-grown fragments from 

 the ruins of another world." This hypothesis, says its dis- 

 tinguished author, " may seem wild and visionary ; all I 

 maintain is that it is not unscientific." Professor Huxley, 

 just the year before (1870), also in a presidential address at 

 the same Association, while dealing with the same problem, 

 uses the following remarkable words:— "And looking back 

 through the prodigious vista of the past, I find no record of 

 the commencement of life, and therefore I am devoid of any 

 means of forming a definite conclusion as to the conditions 



