THE ARCTIC SEAS. 147 
is to renew the vital qualities of the blood by 
presenting it to the air, the oxygen in which uniting 
with the blood renders it again fit for sustaining 
life. Butif more blood could be oxygenized at once 
than is wanted for immediate use, and the overplus 
deposited in a reservoir until wanted, respiration 
could be dispensed with for a while. This is actually 
what the wisdom of God has contrived in the Whale. 
The exhausted blood, which is returned by the veins, 
having been renewed by its communication with the 
air in the lungs, is carried to the heart, whence only 
a part is carried away into the system, the remainder 
‘being received into a great irregular reservoir, con- 
sisting of a complicated series of arteries, which first 
lines a large portion of the interior of the chest, then 
insinuating itself between the ribs, forms a large 
cushion outside of them near the spine, and also 
within the spinal tube, and even within the skull. 
The blood thus reserved is poured into the system 
as it is needed, and thus prevents the necessity of 
frequent access to the surface. 
It ig an object of importance that the act of breath- 
ing should be performed with as little effort as possible, 
and therefore the windpipe is made to terminate 
not in the mouth, nor in nostrils placed at the 
extremity of the muzzle. If this were the case it 
would require a large portion of the head and body to 
be projected from the water, or else that the animal 
should throw itself into a perpendicular position; 
either of which alternatives would be inconvenient 
when swimming rapidly, as, forexample, endeavouring 
to escape when harpooned. The windpipe, there- . 
