84 BIOLOGICAL LECTURES. 



is troubled with trusts, monopolies, strikes, theories of taxa- 

 tion, of protection, of values, of liberty, of free-will, of the 

 family, of education, of heredity, of life itself ; and who shall 

 deliver us ? To say that science will may be true enough, but 

 she cannot to-day. 



In his Locksley Hall Tennyson wrote more than fifty years 



ago : 



" Science moves but slowly, slowly, 

 Creeping on from point to point." 



And that was true then, and in large measure is true to-day, 

 concerning all those matters that relate more nearly to us in 

 our everyday lives. When we laud science, and tell how 

 much has been accomplished within the past fifty years, it is 

 just as well to remember that what has been achieved in this 

 domain has been mostly in the purely mechanical field. We 

 feel quite sure we now know how the Solar system came to be 

 as it is, through a series of slow changes by which a huge 

 molecular cloud of dust in space becomes a body of rotating 

 globes revolving about a central hot mass. We feel quite 

 confident that what we call the doctrine of energy is true, and 

 that it is not created or annihilated by any processes in our 

 experience. We are almost, if not quite convinced that the 

 animals and plants upon the earth to-day are the descendants 

 in unbroken line from the simplest microscopic forms of living 

 things in the far off geologic ages, and we put all these things 

 together and call the process of becoming something different, 

 evolution ; and for convenience we call some mechanical 

 science, and some molecular science, and some biologic science, 

 according as the subject-matter is among big bodies or little 

 bodies or living bodies. But it is sometimes forgotten or 

 overlooked that the same forces are at work with the little as 

 with the big bodies, and that no body, large or small, can be 

 separated from the action of all the rest, and that no particle 

 of matter ever lets go its grip on any other one. These things, 

 I have said, we think we know ; but may I not say we do know, 

 if we really do know anything? If there be any doubt about 

 gravitation, about the laws of energy, about the multiplication 

 table, then one may harbor doubts about any thing he pleases ; 



