VIII.] HOMOLOGIES. 169 



- CHAPTER Via 



HOMOLOGIES. 



Animals made up of Parts mutually related in Various Ways. What Homology is. 

 Its Various Kinds. Serial Homology. Lateral Homology. Vertical Homology. 

 Mr. Herbert Spencer's Explanations. An Internal Power necessary, as shown by 

 Facts of Comparative Anatomy. Of Teratology. M. St Hilaire. Prof. Burt Wilder- 

 Foot-wings. Facts of Pathology. Mr. James Paget Dr. William Budd. The 

 Existence of such an Internal Power of Individual Development diminishes the Im- 

 probability of an Analogous Law of Specific Origination. 



THAT concrete whole which is spoken of as " an indi- 

 vidual " (such, e. g., as a bird or a lobster) is formed of a 

 more or less complex aggregation of parts which are 

 actually (from whatever cause or causes) grouped together 

 in a harmonious interdependency, and which have a multi- 

 tude of complex relations among themselves. 



The mind detects a certain number of these relations 

 as it contemplates the various component parts of an 

 individual in one or other direction as it follows up 

 different lines of thought. These perceived relations, 

 though subjective, as relations, have nevertheless an 

 objective foundation as real parts, or conditions of parts, of 

 real wholes ; they are, therefore, true relations such, e. g., 

 as those between the right and left hand, between the hand 

 and the foot, etc. 



The component parts of each concrete whole have also 

 a relation of resemblance to the parts of other concrete 

 wholes, whether of the same or of different kinds, as the 

 resemblance between the hands of two men, or that between 

 the hand of a man and the fore-paw of a cat. 

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