The Making of Species 
potent than the devastation caused by those 
creatures which feed upon it. Let us, however, 
first briefly set forth some of the checks on 
the multiplication of organisms which Darwin 
mentions in the Origen of Speczes. 
“Eggs, or very young animals,” he says, 
“seem generally to suffer the most, but this is 
not invariably the case.” This is, as we have 
already insisted, a most important point to be 
borne in mind, especially when considering the 
various current theories of animal colouration. 
When once the average animal has become adult 
its chances of survival are enormously increased. 
A second check mentioned by Darwin is the 
limitation of food supply. ‘‘ The amount of food 
for each species,” he writes (p. 84), “of course 
gives the extreme limit to which each can 
increase; but very frequently it is not the 
obtaining food, but the serving as prey to other 
animals, which determines the average numbers 
of a species. Thus there seems to be little 
doubt that the stock of partridges, grouse, and 
hares on any large estate depends chiefly on 
the destruction of vermin. ... On the other 
hand, in some cases, as with the elephant and 
rhinoceros, none are destroyed by beasts of 
prey.” 
We are inclined to think that neither the food 
limit nor the beasts of prey are a very important 
check on the multiplication of organisms. The 
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