THE LAW OF LIKENESS, AND ITS WORKING. 229 



just as, in short, our entire bodies represent so much 

 physical matter, which appears as the outcome of a previous 

 age, and, indeed, as the cumulative products physical and 

 mental of many antecedent generations. The study of the 

 law of likeness, as applied to peculiarities of mind, has 

 materially benefited from the advances in the means of 

 physical research which recent years have brought Indeed, 

 to the merely casual observer there can appear little doubt 

 that the domain of mental science is being invaded on more 

 than one side by the sciences which deal more especially 

 with the material world and with the physical universe 

 around us. When physiologists discovered that the force 

 or impulse which travels along a nerve, which originates in 

 the brain, and which represents the transformation of thought 

 into action, is nearly allied to the electrical force, now one 

 of man's most useful and obedient ministers, one avenue 

 to the domain of mind was opened up. And when physio- 

 logists, through the aid of delicate apparatus, were actually 

 enabled to measure the rate at which this nerve-force travels 

 along the nerve-fibres, it may again be said that physical 

 science was encroaching on the domain of mind, being in 

 a certain sense thus enabled to measure the rapidity of 

 thought. 



A study, exemplifying in a more than ordinary degree 

 .the application of the methods of physical science to the 

 explanation of states of mind, and to the results of the 

 operation of the law of likeness, was brought under the notice 

 of the members of the British Association at the meeting 

 of that body for 1877. I n tne department of Anthropology, 

 the science investigating the physical and mental consti- 

 tution of the races of man, Mr. Francis Galton, as president 

 of this section, devoted his address to the exposition of the 

 classification or arrangement of groups of men, according to 

 their habits of mind, and their physiognomy. 



Of the curious and absorbing nature of such a study, 

 and of its connection with heredity, little need be said. 

 Lavater's method of pursuing the study of character through 



