i 5 2 THE POPULAR SCIENCE MONTHLY. 



architecture, and that of the ant, with its mixed societies. Before in- 

 quiring whether it might not be possible to explain even such amazing 

 instincts by habit and inherited tendency, it is important at the outset 

 to remove an objection that might be supposed unanswerable. Those 

 individuals that have these instincts in the hive or in the ant-hill are 

 neuters that is to say, they are neither male nor female, and must 

 consequently die without posterity. How explain the way in which a 

 habit acquired by a neuter can be transmitted, can grow into an in- 

 stinct, in the neuters of following generations, which will not descend 

 from that first one? Yet the difficulty is not so great as it seems, and 

 Darwin points it out very well. Indeed, it is not the instincts of the 

 neuters which concern him, but it is the special organic modifications 

 that these present, in connection with their social duties with some, 

 labor, and with others, fighting ; but the reasoning he employs can be 

 applied as well to instincts, behind which there always apj>ears, as we 

 see by a little reflection, that latent modification of the cerebral organ 

 through which the transmission has taken place. 



Darwin begins with a reminder that the principle of natural selec- 

 tion is true as well for communities as for individuals. The strength of 

 a single male in a wild herd, the extraordinary fecundity of a single fe- 

 male, will be the elements of prosperity. The herd will succeed better 

 than the rest. The qualities of the individual from which it draws its 

 advantage will have a chance of being transmitted at first to all the 

 herd, and this, more and more favored in the struggle against the 

 outer world, will absorb the rest. The modification, at first individual, 

 will become general. It would be the same if the member of the herd 

 benefited in the beginning had been a neuter. We are still speaking 

 of external forms. Let us suppose that a certain number of neuters 

 may have brought from birth a favorable organic modification into a 

 community of insects, and that by this the community has prospered ; 

 the males and females who have produced these neuters will then have, 

 by them, the greatest possible chances of posterity. It may happen 

 thenceforward that they transmit to their descendants what they had 

 themselves that is to say, the property of procreating neuters having 

 the same favorable organic modification and we thus fall back into 

 the common process of natural selection. Such is Darwin's explana- 

 tion ; he is well aware, when he gives it, complex as it is, that it is the 

 touchstone of his theory, the side whence attack will come ; therefore, 

 how he strengthens his arguments ! He is no longer satisfied with ex- 

 plaining, he demonstrates ; he is supposed to have exhausted his rea- 

 sons, and this is the very moment he chooses for an appeal to experi- 

 ment, and to the proof of that kind of paradox that might be called 

 "hereditary tendency in sterility." There are oxen with horns a little 

 longer than those of the bulls and heifers that produced them. " Well," 

 says Darwin, "pair together, by attentive selection, the fertile de- 

 scendants of the bulls and heifers that produced the oxen w 7 ith longer 



