7. A Ganglion, or what is vulgarly called a "weak" or "weeping" sinew, is the swelling of a bursa. [Footnote: A bursa is a small sack containing a lubricating fluid to prevent friction where tendons play over hard surfaces. There is one shaped like an hourglass on the wrist, just at the edge of the palm. By pressing back the liquid it contains, this bursa may be clearly seen.] It sometimes becomes so distended by fluid as to be mistaken for bone. If on binding something hard upon it for a few days it does not disappear, a physician will remove the liquid by means of a hypodermic syringe, or perhaps cause it to be absorbed by an external application of iodine.
PRACTICAL QUESTIONS.
1. What class of lever is the foot when we lift a weight on the toes?
2. Explain the movement of the body backward and forward, when resting upon the thigh bone as a fulcrum.
3. What class of lever do we use when we lift the foot while sitting down?
4. Explain the swing of the arm from the shoulder.
5. What class of lever is used in bending our fingers?
6. What class of lever is our foot when we tap the ground with our toes?
7. What class of lever do we use when we raise ourselves from a stooping position?
8. What class of lever is the foot when we walk?