THE MALTHUSIAN LAW 23 



not supposed to advance in serried ranks against 

 another, wolves against bears, eagles against vul- 

 tures, firs against beeches and so forth. The com- 

 petition is internal, amongst the individuals of a 

 species. Darwin applied the Malthusian law of 

 population to the animal and vegetable kingdoms 

 generally. All organisms tend to multiply at a rate 

 that would rapidly outstrip the food-supply. It 

 is easy to realize the effect of unchecked multiplica- 

 tion in the case of organisms that give rise to immense 

 numbers of young every year. A turbot, for instance, 

 can produce as many as fifteen millions of eggs 

 in a season, so that if all the descendants of a single 

 pair of turbot were to survive, the huge area of the 

 oceans would be filled with a solid mass of fishes. 

 Darwin's famous calculation about elephants, which 

 are extremely slow breeders, showed that at the end 

 of the fifth centurj/, if all the descendants survived to 

 the full term of their life, the Hving progeny of a 

 single pair would number over fifteen millions. In 

 my book on The Childhood of Animals, I suggested 

 that the difference between the effective multipli- 

 cation of organisms producing a very large number 

 of young and of organisms producing a small number 

 tends to be obliterated, from the circumstance that 

 in the first case there is a heavy destruction of 

 the helpless young, and in the second case the 

 smaller families usually receive useful parental 

 assistance and protection. With small families as 

 with great, however, the total result is that too many 

 young are produced, and there is an active competi- 

 tion among the young and among the adults not only 

 for food, but for other necessary conditions of hfe, 



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