FOREWORD 5 



Another very strong point in favour of our view, 

 and one that I have during many years urged, is 

 the fact that the lowest forms of life still exist 

 all over the surface of the earth, as might be ex- 

 pected if they have been and are constantly surg- 

 ing up from new-born units of living matter. But 

 the doctrine of evolution being true, it seems im- 

 possible to suppose that such simple and at the 

 same time highly mutable living things could have 

 gone on reproducing their like, with little or no 

 change, through all the untold ages of the world's 

 historv. Does not the evolution theory of itself 



i 



tend to negative such a supposition, implying, as 

 it does, that living things, owing to the nature of 

 the matter of which they are constituted and their 







intrinsic tendency to undergo change, have, in fact, 

 been continually though slowly changing, as evi- 

 denced by the past and present extraordinary 

 diversity of the representatives of the Vegetal and 

 the Animal Kingdoms ? 



But the weighing in the balance of these mere 

 relative probabilities will never suffice to settle the 

 question whether living things are or are not still 

 coming into existence bv means of so-called " spon- 



c^ 



taneous generation." Xature has to be questioned 

 by the institution of proper experiments. 



