ANIMAL PEDIGREES 195 



young friends, who was one and the same person 

 for all three, and who forms the true link or bond 

 of union between them. If once these relationships 

 are determined correctly, and the diagram con- 

 structed aright, then it expresses facts, and facts 

 only, and can never be disturbed. It matters not 

 what the occupations or residences of the three 

 may be ; they may never see one another, never 

 even suspect one another's existence. It makes 

 no difference how many people may be living con- 

 temporaneously, how many may have preceded, 

 how many may be born in after ages ; this little 

 bit of history remains untouched and absolutely 

 true for all time. It is for this reason that gene- 

 alogy or blood relationship affords the only satis- 

 factory basis for a classification of men ; and we 

 shall find that the same considerations apply to the 

 lower animals as well. 



One further matter of a preliminary nature 

 requires mention. It is customary in preparing 

 genealogical tables to construct them as is done 

 above, starting from some one more or less remote 

 ancestor, and following upwards the branches 

 representing his descendants, so that the whole 

 diagram takes the form of an upright tree. It 

 should be noted however that in a certain sense 

 the diagram would be more correct if it were 

 inverted. In tracing back human pedigrees there 

 is a marked tendency to follow out one special line 

 of descent, and to concentrate attention on one 

 particular ancestor from whom we desire to make 

 our line arise, ignoring the fact that there were 



