ANIMAL PEDIGREES 197 



find that the existence of a single man to-day 

 involves the existence, a thousand years ago, of 

 over a thousand millions of ancestors; and at the 

 commencement of the Christian era of nearly 

 seventy thousand millions of millions of ancestors : 

 a state of things which would involve serious re- 

 consideration of the dimensions of the earth. 



Genealogical trees, such as I have described, we 

 are all familiar with. Furthermore we know that 

 the principles employed in constructing them are 

 not confined to Smith and Jones and the kings and 

 queens of England, but apply to the lower animals 

 as well. The pedigrees of racehorses, and of other 

 artificially bred animals, such as cattle, sheep, pigs, 

 dogs, pigeons, poultry, etc., have for many years 

 past been kept with the most scrupulous care; and 

 there are men who could tell you in detail the 

 pedigree of the winner of last year's Derby or Leger, 

 who would be sorely perplexed if asked for their 

 own, and would perhaps prefer that the results of 

 researches on this point should not be made too 

 public. 



We all recognise that the cats and rabbits and 

 dogs of to-day did not come into existence spon- 

 taneously, but are descended from the cats, rabbits, 

 and dogs of preceding generations, decades, or 

 centuries ; and that the same applies to birds, to 

 butterflies, to sea anemones, or to any other animals 

 we like to think of. We have now merely to 

 enlarge our sphere of action, to widen our boundaries 

 with regard to such genealogies, and we find 

 ourselves face to face with the great problem with 



