ORGAXIC EVOLUTION — PHYSICAL 19 



they do any other given individual. For instance, if 

 before a child is born we indicate any individual of our 

 acquaintance, the chances are immensely greater that 

 the child when grown will resemble a particular 

 ancestor than that he will resemble the person indicated. 

 That is to say, there is a greater tendency for the child 

 to vary from its parents in the direction of its ancestry 

 than in any other given direction. Now if the parent 

 has varied from the grandparent in any other direction 

 than towards the ancestry, this, the child's variation 

 towards the ancestry, is evidently an omission of the 

 last step made in the evolution of the race. It is what 

 is known as atavism} and is sometimes carried so far 

 that the variations {i. c. the evolution) of hundreds of 

 ancestors nearest it are omitted, and the child resembles 

 some extremely remote ancestor, being ajie-like in 

 features, especially in times of famine, when want of 

 nourishment checks the development, and sometimes 

 being covered Avith long hair. So also the progeny of a 

 pair of thoroughbred horses is sometimes an "arrant 

 weed," or it may revert to an even more remote 

 ancestor, by showing zebra-like stripes. So also "a 

 blue pigeon, like the ancient Columba Livia, may be 

 hatched in the dovecot." On the other hand, the 

 l^rogeny of a pair of ordinary horses never has the 

 peculiar characteristics of the racer; nor has the 

 progeny of a blue pigeon ever those of the pouter or 

 fantail. 



It is well known that race-horses have been developed 

 by an extremely stringent process of artificial selection. 

 I believe I am right in saying that when this process 



• ' Atavism, which is the name given to the recurrence of 

 ancestral traits, is proved by many and varied facts. In the 

 picture-galleries of old families, and on the monumental brasses 

 in adjacent churches, are often seen types of feature that are still, 

 from time to time, repeated in members of their families." 

 — Herbert Spencer's Frinciphs of Bioloaij, vol. i. p. 252. 



