6 
you could not sail a ship across to Ireland. With this enor- 
mous reproduction, therefore, there comes in necessarily the 
second great law, requiring enormous destruction to keep 
the thing at a normal limit. 
The third law is a very curious one, and I don’t think 
it is well known. We might call it one of retardation of 
development. I never heard anybody attach proper im- 
portance to it. You will probably, some of you who are 
fishermen, have heard that when a lake or reservoir is made 
on a small river it is discovered that there are much larger 
fish in the reservoir than there were inthe river originally. 
If you were to turn a large number of calves into a field, 
and there was not sufficient food and room for them they 
would die. In the same way, if you were to set a lot of 
seeds in the garden, and you set them so close that there 
was not room for them they also would die. It is not so 
with fishes, or with most marine and fresh water animals, 
probably with all. I have tried many sorts, and this special 
and most curious law affects them all. If the environment 
is such that there is not. room to grow; of im there is 
not sufficient food, the creatures may remain healthy, but 
they will be small, they will never grow to their full 
proportions until the conditions are favourable; the con- 
sequence is you will have a large stock of tiny fish. I 
was puzzled for many years to understand what the meaning 
of this could be, until it struck me that the explanation was 
