250 LIFE OF PROFESSOR HUXLEY CHAP. X1H 



with the theory of transmutation. In other words, I 

 think trammutation may take place without transition. 



Suppose that external conditions acting on species A 

 give rise to a new species, B ; the difference between the 

 two species is a certain definable amount which may be 

 called A-B. Now I know of no evidence to show that 

 the interval between the two species must necessarily be 

 bridged over by a series of forms, each of which shall 

 occupy, as it occurs, a fraction of the distance between 

 A and B. On the contrary, in the history of the Ancon 

 sheep, and of the six-fingered Maltese family, given by 

 Reaumur, it appears that the new form appeared at once 

 in full perfection. 



I may illustrate what I mean by a chemical example. 

 In an organic compound, having a precise and definite 

 composition, you may effect all sorts of transmutations by 

 substituting an atom of one element for an atom of another 

 element. You may in this way produce a vast series of 

 modifications but each modification is definite in its 

 composition, and there are no transitional or intermediate 

 steps between one definite compound and another. I 

 have a sort of notion that similar laws of definite com- 

 bination rule over the modifications of organic bodies, 

 and that in passing from species to species " Natura fecit 

 saltum." 



All my studies lead me to believe more and more in 

 the absence of any real transitions between natural groups, 

 great and small but with what we know of the physi- 

 ology of conditions [?] this opinion seems to me to be 

 quite consistent with transmutation. 



When I say that no evidence, or hardly any, would 

 justify one in believing in the rise of a new species of 

 Elephant, e.g. out of the earth, I mean that such an 

 occurrence would be so diametrically contrary to all ex- 

 perience, so opposed to those beliefs which are the most 

 constantly verified by experience, that one would be 

 justified in believing either that one's senses were deluded, 



