LIKENESSES; OR, PHILOSOPHICAL ANATOMY. 



rpO say of any man that ' he does not know a hand from a 

 -*- foot ' is to state that his power of estimating difference 

 is defective in an extreme degree, and this statement also 

 seems to imply that such defect is even more remarkable 

 than would be its opposite — namely, a failure in apprehend- 

 ing the likeness which exists between those two parts. 

 Indeed, to pass from a recognition of such unlikeness 

 to an apprehension of such likeness — or, as it is called, 

 ' Homology ' — is to make a step in advance. Our apprecia- 

 tion and comprehension of the world around us is but a con- 

 tinued repetition, on an ever-widening scale, of similar suc- 

 cessive processes of analysis and synthesis. In each branch 

 of science, along with our keener and keener perception 

 of differences, we come to perceive more and more recondite 

 relations of agreement. The telescope and the microscope, 

 the chemical laboratory and the dissecting-room, at first 

 enable us to detect more and more hidden differences m 

 sidereal masses, in animal tissues, in atomic relations, and 

 nerve distributions. Yet, afterwards, the very same agencies 

 enable us to discover facts which tend to harmonise in cor- 

 responding unities the previously discovered diversities of 

 nerve distribution, of chemical relation, of histological con- 

 dition, and (by spectrum analysis) of sidereal constitution. 



In however many directions the human mind sends forth 

 its energ}' upon surrounding nature, its activity brings just 



