THE THEORY OF NATURAL SELECTION. 281 



Struggle for Life.' Mr Alfred Russell Wallace has a 

 conjoint claim to the discovery of this principle, as he 

 published similar views to those of Mr Darwin in a 

 memoir entitled ' On the Tendency of Varieties to depart 

 indefinitely from the Original Type,' which appeared in 

 the Journal of the Linnean Society in 1859, in the same 

 year as the first edition of the ' Origin of Species' was 

 given to the world. It is, as has been seen, an error 

 to regard Mr Darwin as the originator of the theory 

 of Evolution, as applied to animals and plants. It is 

 the ' Theory of Natural Selection ' a theory which 

 explains how evolution has taken place with which 

 his name will be always associated ; and it is this theory 

 alone of which we propose here to give a general out- 

 line. 



The bases of the 'Theory of Natural Selection' may 

 be laid down in the following propositions : 



(i) The first proposition in the Theory of Natural 

 Selection embraces what has been called the ' Malthusian 

 law of increase' the law, namely, that all living beings 

 tend to increase more rapidly than their means of 

 subsistence. The tendency of living beings, in fact, is 

 to increase in a geometrical ratio, and this is true not 

 only of all animals but also of all plants. In support 

 of this law it is not necessary to take the cases of 

 animals so prolific as the cod, the female of which 

 produces annually about ten millions of ova; for the 

 same law is exemplified quite as well by the elephant, 

 which is considered to be the slowest breeder of all 

 animals. Upon this point Darwin has made an interest- 

 ing calculation. The elephant begins to bear young 



