QUESTIONS 
441 
body feels fit and full of energy. The physical examination 
of the drafted men in the United States during 1917-1918 
indicates that we have not paid enough attention to keeping 
our bodies in physical condition and when the opportunity 
came for many to render one of the greatest services that one 
can for his country, they were found to be physically unfit. 
What man can take pride in being physically unfit to serve 
his country? It is our duty to take our physical exercises 
seriously in order that we make our bodies as strong and 
vigorous as possible. 
SUMMARY 
Man is able to move about as other animals. This he does 
by means of his muscles and skeleton, under the direction 
of the nervous system. The skeleton is covered by muscles 
and skin. Bones grow and are fed just like muscles or any 
other tissue in the body. The bones of the skeleton move by 
means of joints which are held in place by ligaments. Bones 
grow new bone, as is seen in the broken femur. There is a 
definite plan of structure to all bones. The muscles are the 
flesh covered by the skin. The muscles are both voluntary 
and involuntary. ' Muscles are important both in the total 
weight of the body and in the numerous movements that they 
produce. Each muscle causes movement through the action 
of its individual cells, which are supplied by nerves and 
blood vessels. The muscle protoplasm is supplied with food 
for contraction purposes and food to repair the wastes. 
Muscles become fatigued and require food, rest, and the re¬ 
moval of wastes in order to recover from this fatigue. Physi¬ 
cal training is valuable in helping to develop properly all 
the muscles of the body, in keeping the body well, and in 
making it the best body possible. 
QUESTIONS 
How does the skeleton of man compare with that of the crayfish ? 
How do bones grow? Why do they grow? Where is there the most 
