194 FRAGMENTS OF SCIENCE 



conquests of the comparative anatomist and physiologist, 

 revealing the structure of every animal, and the function 

 of every organ in the whole biological series, from the 

 lowest zoophyte up to man. The nervous system had 

 been made the object of profound and continued study, 

 the wonderful and, at bottom, entirely mysterious control- 

 ling power which it exercises over the whole organism, 

 physical and mental, being recognized more and more. 

 Thought could not be kept back from a subject so pro- 

 foundly suggestive. Besides the physical life dealt with 

 by Mr. Darwin, there is a psychical life presenting similar 

 gradations, and asking equally for a solution. How are 

 the different grades and orders of Mind to be accounted 

 for? What is the principle of growth of that mysterious 

 power which on our planet culminates in Reason? These 

 are questions which, though not thrusting themselves so 

 forcibly upon the attention of the general public, had not 

 only occupied many reflecting minds, but had been for- 

 mally broached by one of them before the "Origin of 

 Species" appeared. 



With the mass of materials furnished by the physicist 

 and physiologist in his hands, Mr. Herbert Spencer, twenty 

 years ago, sought to graft upon this basis a system of psy- 

 chology; and two years ago a second and greatly ampli- 

 fied edition of his work appeared. Those who have occu- 

 pied themselves with the beautiful experiments of Plateau 

 will remember that when two spherules of olive-oil, sus- 

 pended in a mixture of alcohol and water of the same 

 density as the oil, are brought together, they do not im- 

 mediately unite. Something like a pellicle' appears to be 

 formed around the drops, the rupture of which is imme- 

 diately followed by the coalescence of the globules into 



