CHAPTER VIII. 



HOMOLOGIES. 



Animals made-up of parts mutually related in various ways. "What homo- 

 logy 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 ter- 

 atology. M. St. HiMre. Professor 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 

 improbability of an analogous law of specific origination. 



THAT concrete whole which is spoken of as " an individual " 

 (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 multitude of complex 

 relations amongst themselves. 



The mind detects a certain number of these relations as 

 it contemplates the various component parts of an indi- 

 vidual in one or other direction as it follows up different 

 lines of thought. These perceived relations, thougji sub- 

 jective, as relations, have nevertheless an objective founda- 

 tion 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, &c. 



