6. Describe the structure of a bone. What is the object of the filling? Why does the amount vary in different parts of a bone? What is the appearance of a bone seen through a microscope?
7. What is the periosteum? Is a bone once removed ever restored? What are the lacunæ? The Haversian canals? Why so called? Ans. From their discoverer, Havers. Define a bone. [Footnote: Bone structure may be summarized as follows: A bone is a collection of Haversian elements, or rods. An Haversian element consists of a tube surrounded by lamellæ, which contain lacunæ, connected by canaliculi.—DR. T. B. STOWELL.] What occupies the lacunæ? Ans. The bone cells (osteoblasts). How do bones grow?
8. Illustrate. How does a broken bone heal? How rapidly is bone produced? Illustrate. Objects of "splints"? Describe how a joint is packed. Lubricated.
9. How are the bones tied together? What is a tissue? Illustrate. Name the three general divisions of the bones. What is the object of the skull? Which bone is movable? How is the lower jaw hinged? Describe the construction of the skull. What is a suture?
10. Tell how the peculiar form and structure of the skull adapt it for its use. Illustrate the impenetrability of the skull.
11. Describe the experiment of the balls. What does it show? What two cavities are in the trunk? Name its principal bones. Describe the spine.
12. What is the object of the processes? Of the pads? Why is a man shorter at night than in the morning? Describe the perfection of the spine.
13. Describe the articulation of the skull with the spine. Why is the atlas so called?
14. Describe the ribs. What is the natural form of the chest? Why is it made in separate pieces? How does the oblique position of the ribs aid in respiration? (See note, p. 80.)
15. How do the hipbones give solidity? What two sets of limbs branch from the trunk? State their mutual resemblance. Name the bones of the shoulder. Describe the collar bone.