- LORD SALISBURY ON EVOLUTION. 575* 



from the possession of the same variation by the animal with 

 which it is mated ; and this belief is held by men who, as breed- 

 ers, stake large profits on its truth. How, then, can it be said 

 that without the union of two similarly varied individuals, " the 

 new breed would never even begin, let alone the question of its 

 perpetuation after it had begun." And here, to show still more 

 clearly how experience negatives Lord Salisbury's assumption, let 

 me give some evidence furnished not by domestic animals, but by 

 human beings. Referring to a controversy which I have recently 

 been carrying on with Prof. Weismann, Dr. Lindsay Johnson, 

 F. R. C. S., who practices as an ophthalmic surgeon, and who tells 

 me that the experience of other oculists verifies his own, testifies 

 to the transmission of acquired myopia through several genera- 

 tions. He says (I quote with his permission) : 



" I have seen a very large number of myopic patients who have had 

 long-sighted parents and gi'andparents, but who have, during their studies 

 or occupations, acquired a considerable degree of short sight and astigma- 

 tism, and tiien having had children from a noi'mal or long-sighted wife 

 (witb normal-sighted parents and grandparents) it has been found that 

 several of these children have grown up myopic and perpetuated it to their 

 offspring again." 



And he sends me a genealogical tree showing that in a family of 

 six children descending from long-sighted ancestry on both sides, 

 four remained normal- sighted, but two, who were miniature paint- 

 ers, became myopic. Of these one, marrying a normal-sighted 

 wife, had two children, of whom one was myopic ; and the other, 

 marrying also a normal- sighted wife, had three children, all my- 

 opic. Two of these three married normal-sighted wives, and 

 among their children there was in each case one who had become 

 myopic, while the rest are as yet too young to display the defect, 

 for it never occurs until after eight years old. That the inherited 

 trait is in this case one caused by use, and not one arising spon- 

 taneously, does not affect the issue. There is proof that a modifi- 

 cation of structure existing in one parent may descend to children 

 when no similar modification is possessed by the other parent; 

 and, further, that this modification may be re-transmitted, also 

 without the aid of the second parent : facts which negative Lord 

 Salisbury's assumption. 



Let us now consider what is the corollary as respects modifica- 

 tion of varieties and formation of species. Travelers tell us that 

 the Bushmen are so long-sighted that they can see as far with 

 the naked eye as a European can with a telescope. Allowing for 

 some exaggeration, it is safely to be inferred that they have marvel- 

 ous powers of discerning objects at great distances. How has this 

 trait arisen ? Small men as they are, wandering about in single 

 families, Bushmen have to guard against enemies, brute and hu- 



