Chap. XXI.] AND CONCLUDING REMARKS. 369 



and constitution, both of high and of the most trifling im- 

 portance — the rudiments which he retains, and the abnor- 

 mal reversions to which he is occasionally liable — are facts 

 which cannot be disputed. They have long been known, 

 but until recently they told lis nothing with respect to 

 the origin of man. Now, when viewed by the light of 

 our knowledge of the whole organic Avorld, their meaning 

 is unmistakable. The great principle of evolution stands 

 up clear and firm, when these groups of facts are consid- 

 ered in connection with others, such as the mutual afiini- 

 ties of the members of the same group, their geographical 

 distribution in past and present times, and their geological 

 succession. It is incredible that all these facts should 

 speak falsely. He who is not content to look, like a sav- 

 age, at the phenomena of Nature as disconnected, cannot 

 any longer believe that man is the work of a separate act 

 of creation. He will be forced to admit that the close re- 

 semblance of the embryo of man to that, for instance, of 

 a dog — the construction of his skull, limbs, and whole 

 frame, independently of the uses to which the parts may 

 be put, on the same plan with that of other mammals — 

 the occasional reappearance of various structures, for in- 

 stance, of several distinct muscles, which man does not 

 normally possess, but w^hich are common to the Quadru- 

 mana — and a crowd of analogous facts — all point in the 

 plainest manner to the conclusion that man is the co-de- 

 scendant with other mammals of a common progenitor. 



We have seen that man incessantly presents individual 

 differences in all parts of his body and in his mental facul- 

 ties. These differences or variations seem to be induced 

 by the same general causes, and to obey the same laws as 

 with the lower animals. In both cases similar laws of 

 inheritance prevail. Man tends to increase at a greater 

 rate than his means of subsistence; consequently he is 

 occasionally subjected to a severe struggle for existence, 



