WINTERING. 
521 
ing, the bees are actually feeding upon the store of 
honey taken into the honey-sac (page 60, Vol. L), 
where it is held until appetite requires appeasing. 
Then the stomach mouth — a marvellous structure, lying 
behind the honey-sac — passes a ration backwards to 
the true stomach, whence it enters the fluids of the 
bee, to undergo oxidation, for we have already seen 
that honey, and saccharine substances generally, are the 
materials from which heat is produced (see page 376). 
These consist of two gases, oxygen and hydrogen, in 
the proportions in which they exist in water, in 
combination with carbon ; and although it would be 
scientifically inexact to say that honey consists of 
carbon and water, for our present purpose it is con- 
venient so to regard it. The bees clustering together^ 
if surrounded by the most favourable conditions, are 
able to maintain, in their centre, the 65° previously 
referred to, by the slowest imperceptible breathing; 
but if external temperature sinks, the bees, witliout 
some counteracting action, would be prejudicially 
chilled. This they prevent by elongating and con- 
tracting their abdomens (a movement which may be 
seen in any bees recently settled), thus rapidly drawing 
in and expelling air by the before-mentioned spiracles, 
fourteen in number. The cold, intensifying, needs 
further efforts, and now the wings, gently flapping, 
producing a buzzing murmur audible outside, pump 
the air in and out with vigour, and fill up the tracheae 
(page 147, Vol. I.), and hold off the grip of the enemy; 
for, the more rapidly this breathing is carried on, the 
more oxygen is brought into contact with the honey, 
and the more of it is consumed, and the greater the 
