256 BIOGENESIS AND ABIOGENESIS vill 



place in the past, or ever will take place in 

 the future. With organic chemistry, molecular 

 physics, and physiology yet in their infancy, and 

 every day making prodigious strides, I think it 

 would be the height of presumption for any man 

 to say that the conditions under which matter 

 assumes the properties we call " vital " may not, 

 some day, be artificially brought together. All I 

 feel justified in affirming is, that I see no reason 

 for believing that the feat has been performed 

 yet. 



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 

 of its appearance. Belief, in the scientific sense 

 of the word, is a serious matter, and needs strong 

 foundations. To say, therefore, in the admitted 

 absence of evidence, that I have any belief as to 

 the mode in which the existing forms of life have 

 originated, would be using words in a wrong sense. 

 But expectation is permissible where belief is 

 not ; and if it were given me to look beyond the 

 abyss of geologically recorded time to the still 

 more remote period when the earth was passing 

 through physical and chemical conditions, which 

 it can no more see again than a man can recall 

 his infancy, I should expect to be a witness of the 

 evolution of living protoplasm from not living 

 matter. I should expect to see it appear under 



