5. What constituents of the blood may be regarded as freight and what as agents for carrying this freight?
6. After coagulation, what portions of the blood are found in the clot? What portions are found in the serum?
7. What purposes are served by water in the blood?
8. Show how the blood, though constantly changing, is kept about the same in quantity, density, and composition.
9. In the lungs the blood changes from a dark to a bright red color and in the tissues it changes back to dark red. What is the cause of these changes?
10. If the oxygen and hemoglobin formed a strong instead of a weak chemical union, could the hemoglobin then act as an oxygen carrier? Why?
[pg 037]11. What habits of living favor the development of corpuscles in the blood?
12. Why will keeping the skin clean and active improve the quality of one's blood?
PRACTICAL WORK
To demonstrate the Physical Properties of Blood (Optional).—Since blood is needed in considerable quantity in the following experiments, it is best obtained from the butcher. To be sure of securing the blood in the manner desired, take to the butcher three good-sized bottles bearing labels as follows: