3H SCIENCE PROGRESS 



suppose that life may have been self-constituted, to obtain a 

 hearing, we must discover the means of self-constitution. 



Sir William Tilden, in a letter to The Times (September 10, 

 1912), after referring to the various raw materials available on 

 the earth, remarks : " I venture to think that no chemist will 

 be prepared to suggest a process by which, from the inter- 

 action of such materials, anything approaching a substance of 

 the nature of a proteid could be formed or, if by a complex 

 series of changes a compound of this kind were conceivably 

 produced, that it would present the characters of living proto- 

 plasm." He appears to deprecate discussion of the problem, 

 judging from the concluding sentence of his letter: 



"Far be it from any man of science to affirm that any given 

 set of phenomena is not a fit subject of inquiry and that there 

 is any limit to what may be revealed in answer to systematic 

 and well-directed investigation. In the present instance, how- 

 ever, it appears to me that this is not a field for the chemist 

 nor one in which chemistry is likely to afford any assistance 

 whatever." 



I agree with Sir William Tilden that Prof. Schafer's address 

 " leaves us exactly where we were " and that the " earlier 

 part of the discourse leaves open the question as to a criterion 

 by. which living may be distinguished from non-living matter." 

 But I cannot accept his statement that "we have at present, 

 therefore, no clear idea as to what life is and therefore no 

 clear road open to the study of the conditions under which it 

 originated." 



Like Prof. Schafer, I do not find myself in the least helped 

 by the idea that life has originated elsewhere — by adopting such 

 a conclusion we only shift the difficulty a stage further back. I 

 agree too with Prof. Minchin in thinking, that if life had reached us 

 from other worlds it would have found our earth unprepared to 

 receive it and would have been starved out of existence ; this 

 question of food supply has not been taken into consideration by 

 the advocates of the hypothesis. If there be life elsewhere, on 

 other worlds than ours, the probability is that it more or less 

 resembles life as we know it. To judge from spectroscopic 

 evidence, the materials of which our world consists are those 

 which constitute the cosmos. There is but one element in 

 which the potency of life can be said to exist— the element 

 carbon ; the complexities and variations which are met with in 



