HEREDITY. 125 



can never occur, from the fact that the inheritor is a 

 compromise between two beings, and therefore can 

 not be like either must vary from both. Admitting 

 that all nations of the earth were originally of one 

 blood, the evidence of variability is every- where pro- 

 nounced. If there came from the ark two of a kind 

 (male and female) except so far as Noah was con- 

 cerned, the carnivorous must have destroyed many 

 kinds of animals not mentioned and not represented 

 since that time; and, what is now to be observed, the 

 yellow lion of South Africa will not consort with a 

 black variety in Algiers and Morocco; and the Bengal 

 tiger of India will have nothing to do with the great 

 feline of Thibet, though it be well known that the cat 

 family varies less than almost any other. If ancient 

 notions of heredity be true, how are we to account for 

 the tailless or manx cat of the Isle of Man? Here 

 seems to be a " sport" or saltus as great as that which 

 robs an ape of its caudal appendage ! 



When a sudden and marked change takes place 

 in the organic world, quite violating the accepted or 

 avowed principles of heredity, we are forced to admit 

 something like a saltatory influence to account for the 

 spanning of wide gaps in the history of organic life, 

 or for the accomplishment of what has taken place 

 without evidence of the slow transforming processes 

 peculiar to the changes of evolution. We have seen 

 that a plant under unfavorable surroundings may drift 

 backward at a rapid rate. While an upward course 

 must be necessarily slow, a retrograde movement may 

 be in leaps "descensus averni facile est." 



It does not seem that the skeletal parts of a pter- 

 odactyl could be developed slowly ; they should come 

 at a leap, with a bounce. Then how could a bat's 



