19. What is the cause of one's foot being "asleep"? [Footnote: Here the nervous force is prevented from passing by compression. Just how this is done, or what is kept from passing, we can not tell. If a current of electricity were moving through a rubber tube full of mercury, a slight squeeze would interrupt it. These cases may depend on the same general principle, but we can not assert it.—HUXLEY. The tingling sensation caused by the compression is transferred to the foot, whence the nerve starts.]
20. When an injury to the nose has been remedied by transplanting skin from the forehead, why is a touch to the former felt in the latter?
21. Are closely curtained windows healthful?
22. Why, in falling from a height, do the limbs instinctively take a position to defend the important organs?
23. What causes the pylorus to open and close at the right time?
24. Why is pleasant exercise most beneficial?
25. Why does grief cause one to lose his appetite?
26. Why should we never study directly after dinner?
27. What produces the peristaltic movement of the stomach?
28. Why is a healthy child so restless and full of mischief?