opinions on Isolation. 123 



considerable interest in itself, I will quote his remarks 

 in extenso. In his Opening Address to the Liverpool 

 Biological Society, Professor Herdman said : — 



Some of you will doubtless remember that in last year's 

 address, while discussing Dr. Romanes' theory of physiological 

 selection, 1 quoted Professor Flemming Jenkin's imaginary case 

 of a white man wrecked upon an island inhabited by negroes, 

 given as an illustration of the supposed swamping effect by 

 free intercrossing of a marked variety with the parent species. 

 I then went on to say in criticism of the result at which Jenkin 

 arrived, viz. that the characteristics of the white man would be 

 stamped out by intercrossing with the black : — 



"Two influences have, I think, been ignored, viz. atavism, 

 or reversion to ancestral characters, and the tendency of the 

 members of a variety to breed with one another. Keeping to 

 the case described above, I should imagine that the numbers of 

 intelligent young mulattoes produced in the second, third, fourth, 

 and few succeeding generations would to a large extent inter- 

 marry, the result of which would be that a more or less white 

 aristocracy would be formed on the island, including the king 

 and all the chief people, the most intelligent men and the bravest 

 warriors. Then atavism might produce every now and then 

 a much whiter individual— a reversal to the characteristics of 

 the ancestral European— who, by being highly thought of in 

 the whitish aristocracy, would have considerable influence 

 on the colour and other characteristics of the next generation. 

 Now such a white aristocracy would be in precisely the same 

 circumstances as a fa ourable variety competing with its parent 

 species," &c. 



You may imagine then my pleasure when, a few months after 

 writing the above, I accidentally found, in a letter ' written by the 

 celebrated African traveller Dr. David Livingstone to Lord 

 Granville, and dated " Unyanyembe, July ist, 1872," the follow- 

 ing passage : — 



" About five generations ago, a white man came to the high- 

 lands of Basango, which are in a line east of the watershed. 



' In Appendix to H. M. Stanley's .ffow I found Livingstone, 2nd ed. 

 London, 1872, p. 715. 



