ion of acids, or as the result of
the digestive enzymes, and as such becomes the principal form in which
the animal body utilizes the carbohydrates ingested. Under normal
conditions the glucose in the blood is constantly being burned and
replaced; it is only when the body loses to a greater or less degree
the ability to burn the glucose that it accumulates in the blood,
from which it must escape by way of the urine. There are times, such
as when very large quantities of carbohydrates are eaten at once, when
glucose will also appear in the urine; but under such circumstances it
is generally found to be merely temporary, and for this reason, the
condition is known as temporary glycosuria. As a rule, however, the
surplus of glucose absorbed, whether it be eaten as such, or is found
as the result of enzymic action upon the other carbohydrates, is
converted into glycogen and stored in the liver and to a less extent
in the muscles. Glycogen is readily reconverted into glucose, which is
used by the body for the production of energy. It has been estimated
that over half the energy manifested in the human body is derived from
glucose, and it is in this form that the tissues of the body will
ultimately make use of most of the carbohydrates in food. Practically
all of the fruits, and many of the vegetables, are rich in this form
of carbohydrate, but grapes contain more than any of the other fruits,
while sweet corn, onions, and unripe potatoes contain appreciable
amounts.

~Fructose.~--The second member of the monosaccharide group is more or
less associated with glucose in plant and fruit juices, and is used
like that substance for the production of glycogen in the body. Eaten
as such, or produced as the result of digestive action upon cane
sugar, fructose is changed into glycogen, chiefly upon entering the
liver, and for this reason will not be found to enter largely into the
blood of the general circulation.[3]

Honey is the most abundant source of fructose in nature.

~Galactose.~--This sugar, unlike the other members of this group, is
not found free in nature, but it is produced as the result of
hydrolysis of milk sugar, either by enzymes or by acids. Like glucose
and fructose, galactose seems to promote the production of glycogen in
the body. Certain substances known as galactosides, which are
combinations of galactose and some substances other than
carbohydrates, are found in the nerve and brain tissues of the animal
bod