2 28 THE POPULAR SCIENCE MONTHLY. 



animal or plant which is well adapted to its conditions of life is 

 more likely to live than an animal which is ill adapted. I have 

 some difficulty in imagining how any other arrangement can even 

 be supposed possible. It seems to be almost an identical proposi- 

 tion that the healthiest and strongest will generally live longest ; 

 and the conception of a " struggle for existence " only enables us 

 to understand how this results in certain progressive modifica- 

 tions of the species. If we could even for a moment have fancied 

 that there was no pain and disease, and that some beings were 

 not more liable than others to those evils, I might admit that 

 the new doctrine has made the world darker. As it is, it seems to 

 me that it leaves the data just what they were before, and only 

 shows us that they have certain previously unsuspected bearings 

 upon the history of the world. 



One other point must be mentioned. Not only are species 

 interdependent as well as partly in competition, but there is an 

 absolute dependence in all the higher species between its different 

 members which may be said to imply a de facto altruism, as the 

 dependence upon other species implies a de facto co-operation. 

 Every animal, to say nothing else, is absolutely dependent for a 

 considerable part of its existence upon its parents. The young 

 bird or beast could not grow up unless its mother took care of it 

 for a certain period. There is, therefore, no struggle as between 

 mother and progeny, but, on the contrary, the closest possible 

 alliance. Otherwise life would be impossible. The j'oung being 

 defenseless, their parents could exterminate them if they pleased, 

 and by so doing would exterminate the race. This, of course, 

 constantly involves a mutual sacrifice of the mother to her young. 

 She has to go through a whole series of operations, which strain 

 her own strength and endanger her own existence, but which are 

 absolutely essential to the continuance of the race. It may be 

 anthropomorphic to attribute any maternal emotions of the 

 human kind to the animal. The bird, perhaps, sits upon her eggs 

 because they give her an agreeable sensation, or, if you please, 

 from a blind instinct which somehow determines her to the prac- 

 tice. She does not look forward, we may suppose, to bringing 

 up a family, or speculate upon the delights of domestic affec- 

 tion. I only say that as a fact she behaves in a way which 

 is at once injurious to her own chances of survival and abso- 

 lutely necessary to the survival of the species. The abnor- 

 mal bird who deserts her nest escapes many dangers ; but if all 

 birds were devoid of the instinct, the birds would not survive a 

 generation. 



Now, I ask, what is the difference which takes place when the 

 monkey gradually loses his tail and sets up a superior brain ? Is 

 it properly to be described as a development or improvement of 



