efense. In migrating they travel in large herds, but when
feeding they separate into herds of about two or three hundred each.
The leader maintains his position by superior intelligence and brute
force. If he fails in duty he is punished. Scouts go ahead of the herd
in search of new pastures; and guards, or sentinels surround the herd
and guard it while feeding and during the night. When the guards have
been on duty awhile, they give place to fresh guards. In case of
danger, the guards give a signal of alarm by tossing up the head and
bellowing furiously. At this the leader gives a signal and the herd
starts off at once. Bison run swiftly for a short distance, but are
not able to continue a rapid flight. They can run faster than cattle,
however, and when pursued always run against the wind. When surprised
or wounded, they turn upon their assailants and attack them furiously,
fighting with horns and hoofs. They show their rage by thrusting out
the tongue, lashing the tail, and projecting the eyes. At such times
they are fierce and formidable. The enemies of the bison are the
carnivorous animals. A herd of bison has no cause to be afraid of
wolves or bears, but solitary bison are often killed by these
creatures. The cry of a bison resembles that of a groan or grunt.
In case the leader is killed and no bison is able to assert his
authority, there is great confusion until the question of leadership
is settled.

_References_: Richard Irving Dodge, _The Plains of the Great West_,
pp. 119-147. W. T. Hornaday, _The Extermination of the American
Bison_, in "The Smithsonian Report of the U. S. National Museum,"
1887, pp. 367-548. Poole's Index will supply references to magazines,
and the encyclopedias and natural histories will furnish further
facts.

_Lessons IX and X._ Boiling is such a common process that one seldom
thinks of the importance of the discovery of the art. These lessons
will show the child how people may have learned to boil and the
explanation they would be apt to give of the changes which take place
during the process. Boiling was undoubtedly used as a religious
ceremony long before it was used for cooking food.

_Lessons XI and XII._ If possible let the children take a field trip
in connection with these lessons. If there are no nuts or wild fruits
to gather, let the children gather fruits from a garden or some of the
products of the farm. The particular conditions in which the children
are placed will dete