96 CONDITIONS AFFECTING THE 



in its colour, perhaps the minutest circumstance will 

 turn the scale one way or the other. 



Suppose that by a variation of the black race it had 

 produced the white man at any time you know that the 

 Negroes are said to believe this to have been the case, and 

 to imagine that Cain was the first white man, and that we 

 are his descendants suppose that this had ever happened, 

 and that the first residence of this human being was on the 

 "West Coast of Africa. There is no great structural differ- 

 ence between the white man and the Negro, and yet there 

 is something so singularly different in the constitution of 

 the two, that the malarias of that country, which do not 

 hurt the black at all, cut off and destroy the white. Then 

 you see there would have been a selective operation per- 

 formed ; if the white man had risen in that way, he would 

 have been selected out and removed by means of the 

 malaria. Now there really is a very curious case of selection 

 of this sort among pigs, and it is a case of selection of 

 colour, too. In the woods of Florida there are a great 

 many pigs, and it is a very curious thing that they are all 

 black, every one of them. Professor \Vyman was there 

 some years ago, and on noticing no pigs but these black 

 ones, he asked some of the people how it was that they 

 had no white pigs, and the reply was that in the woods of 

 Florida there was a root which they called the Paint Root, 

 and that if the white pigs were to eat any of it, it had the 

 effect of making their hoofs crack, and they died, but if 

 the black pigs eat any of it, it did not hurt them at all. 

 Here was a very simple case of natural selection. A skilful 

 breeder could not more carefully develope the black breed 

 of pigs, and weed out all the white pigs, than the Paint 

 Root does. 



To show you how remarkably indirect may be such 

 natural selective agencies as I have referred to, I will 

 conclude by noticing a case mentioned by Mr. Darwin, 

 and which is certainly one of the most curious of its kind. 

 It is that of the Humble Bee. It has been noticed that 

 there are a great many more humble bees in the neighbour- 

 hood of towns, than out in the open country ; and the 

 explanation of the matter is this: the humble bees build 

 nests, in which they store their honey and deposit the 

 larvae and eggs. The field mice are amazingly fond of the 

 honey and larvae ; therefore, wherever there are plenty of 

 field mice, as in the country, the humble bees are kept 



