io6 Thomas Henry Huxley 



between natural species. The evidence for this we 

 have before our eyes, if we choose to see, on a stock 

 farm; in the breeding yards of any keeper of " fancy " 

 animals ; or in the nursery gardens of any florist. So 

 far, Huxley accepted the Darwinian principle as a defi- 

 nite contribution to knowledge ; and so far the whole 

 body of biologists has followed him. Beyond this the 

 truth of the Darwinian principle is a matter of inference 

 or judgment; of balancing probabilities and improba- 

 bilities. In multitude of counsellors there is said to be 

 wisdom, and what we learn from the counsellors of 

 biology all over the world is that some maintain that 

 natural selection is the only probable agency in effect- 

 ing evolution, and that it is competent to account for 

 all the changes which we know to have taken place ; 

 others hold that its probable influence has been over- 

 rated ; and others, again, think that it has been one of 

 the many causes that have brought about the kaleido- 

 scopic variety of organic nature. Huxley remained to 

 the last among those who distinguished in the clearest 

 way between natural selection as an exceedingly inge- 

 nious and probable hypothesis, and a proved cause; and 

 he was always careful, especially when he was writing 

 for or speaking in the presence of those who like him- 

 self accepted the fact of evolution as proven, to dis- 

 tinguish between this provisional hj-pothesis as to how 

 evolution had come about, and definite knowledge that 

 it had come about in this way. Two passages from 

 Huxley's writings, one written in i860 in the IVesf- 

 viinster Review, and the second written in 1893, in the 

 preface to the volume of his collected essays which 

 contained a reprint of the Westminster ^xWq\&, will make 

 plain the continuity of Huxley's attitude : 



"There is no fault to be found with Mr. Darwin's method, 



