168 
THREK-SPINED STICKEEBACK. 
of Providence, whilst the elegance and complexity of their 
form, only require examination to excite admiration, and their 
habits and instincts are so full of curiosity as to secure 
attention when it has been directed towards Ihem. 
Our Common Sticklebacks are inhabitants of both salt-water 
and fresh, but they do not in preference frequent the open 
sea, and a quiet union of the sea-water with the fresh appears 
the most congenial with their nature, as we may judge by 
the abundance to be met with in such situations. In large 
ponds of this description they increase to an enormous extent, 
and may be seen traversing their daily range again and again, 
in numerous companies, and hunting eagerly for food, which 
appears to be formed of any of the smaller inhabitants of the 
water they are able to swallow. Myriads of the half-developed 
young of flying insects — the smaller creatures whose ollice it 
is to keep down superfluous increase of vegetable life, but 
which themselves might otherwise multiply in numbers too 
great, so as to be among the evils themselves were destined 
to abate,— and, we must add, the young of such fishes as are 
then bursting into life: all of these contribute to the suste- 
nance of these tribes of wandering plunderers, until at last 
their numbers also have grown to be excessive. Birds feed 
on them; but their formidable enemy is man, and with his 
net they are swept to the bank in helpless heaps, to become 
of some service to the people who have been at the trouble 
to catch them. In some places they are employed for the 
purpose of feeding ducks or pigs; and sometimes they are 
drawn on shore in such heaps as to serve for manure, for 
which purpose they are said to be of considerable value, a 
fact not improbable, when, according to Lacepede, they are 
known to afford by pressure a good supply of oil, which we 
suppose can only come from the liver. 
In the Baltic, Professor Nilsson says that about the beginning 
of November, before they retire to their winter quarters, they 
assemble on the coasts of that sea in incredible shoals, and 
are caught in boat-loads by fishermen. The only use made of 
them is to boil them for the purpose of skimming the fluid for 
the oil. A bushel of these fish yields about two gallons of oil. 
The refuse is employed for manure. 
They breed generally in summer, and then it is that the most 
