ON BIOLOGY. 95 



physiology of the Protamaba and the tadpole, and am 

 tree to confess tbat i would be glad to have 11 made c ear 

 to me that ihe living principle, the verv essence of life is 

 identical in all three of these organisms. Still more 

 would I be slad to know the precise difference 'twixt a 

 live amceba and a dead one; 'twixt a live bp-rmatozoon 

 and a dead one; and, finalb , is the unimpregoated ovum 

 of the female endowed with Jife, or is life simply brought 

 to it by the male spermatozoon? Surely ihe >oung 

 science of aetiology has many questions to answer for us. 

 Finally, we have the words of Huxley upon this sub- 

 ject, in his able address on ''spontaneous generation," 

 delivered before the British Association for the Advance- 

 ment of Science, at the Liverpool meeting, in September, 

 1870; and although that is nearly a quarter of a century 

 ago, it yet remains a very clear exriosition of the case, 

 and he then said: "Though I cannot express this convic- 

 tion of mine too strongly, I muse carefully guard myself 

 against the supposition that I intend to suggest that no 

 such thing as abiogenesis ever has taken place in the past 

 or ever will take place in the future. With organic 

 chemistry, molecular physics and physiology }et 

 in their infancy and every day making prodig- 

 ious strides I think it would be the height of presump- 

 tion for any man to say that the conditions under which 

 matter assumes the properties we call 'vital' may not 

 some dav, 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 ad- 

 mitted absence of evidence, that I have any belief as to 

 the mode in which the existing forms of life have origi- 

 nated would be using words in a wrong sense. But expec- 

 tation is permissible where belief is not; and, if it were 

 given me 10 look beyond the abyss of geologically recorded 

 lime 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 forms of great simplicity, 

 endowed, like existing fungi, with the power of deter- 



