The Life Processes of the Individual 147 
stomach. However; pollen contains no starch so that the 
breaking down of starch plays a small part in the digestion 
of the bee. 
The next important constituent of bee food is proteid, 
derived from pollen. Petersen shows the presence of pro¬ 
teolytic ferments in the salivary gland secretions and es¬ 
pecially claims that the layers of peritrophic membrane 
consist largely of such ferments. He also makes the in¬ 
teresting observation that the bee is incapable of digesting 
the proteid from pollen unless the grains are broken before 
they enter the ventriculus, any ones remaining unbroken 
simply passing out in the feces. It would therefore seem 
probable that the pollen is surrounded in the ventriculus 
with the peritrophic layers containing the ferments and is 
then passed on to the small intestine without being broken 
up or absorbed. The use of pollen is more in evidence 
during brood-rearing and it is usually assumed that the 
workers predigest this, or perhaps more correctly, secrete 
a mixture rich in protein for the use of the larvae. However, 
since the mid-intestine of the older larvae contain consider¬ 
able pollen, a large part of their proteid digestion is by their 
own proteolytic ferments. 
Pollen contains considerable oil but Petersen failed to find 
that any of it is digested by the bee, at any rate most of it 
passes through without being broken up or absorbed. 
The retention of feces by bees, so long as they stay in the 
hive, except when dysentery develops, is of importance 
in their management. The relation of this retention to 
the activities of bees in winter is discussed in a previous 
chapter (p. 91). Usually during the active season, when 
feces accumulate most rapidly, there are frequent opportu¬ 
nities for flight and the ejection of feces. 
For bees living only on honey or perhaps on a syrup of 
cane sugar, digestion is reduced to a minimum. It remains 
to be proved whether under such conditions the bees are 
fully nourished. That bees can live over winter without 
pollen is of course not proof that they do not need it then. 
