IN HUMAN PHYSIOL OGT. 187 



28. Why is a healthy child so restless and full of mis- 

 chief? 



Nature prompts it to exercise all the muscles in its body 

 in order to their proper development. 



29. Why is a slight blow on the back of a rabbit's neck 

 fatal? 



. The medulla oblongata is not defended with thick 

 muscles as in man. 



30. Why can one walk and carry on a conversation at 

 the same time ? 



(See Question 13, page 176.) 



3 1. What are the dangers of over-study ? 



(See Hinton's Health and its Conditions, page IQS, et seq., and Cutler's 

 Analytical Anatomy, page 248.) 



Exhaustive mental labor overstrains the delicate nerve- 

 cells of the brain, and the condition of the blood-vessels 

 of the entire body, especially of the vital organs, is regu- 

 lated, moment by moment, by its changing moods. Even 

 the supply furnished the brain is subject to the same 

 influence. Hence results deranged nutrition, impaired 

 circulation, and weakened brain and body. Whenever 

 we consume vital energy faster than it can be replaced, 

 we encroach upon the capital, and thus cause an irrepar- 

 able injury. 



32. What is the influence of idleness upon the brain ? 



If we would have healthy bodies we must have active 

 brains, that the streams of force may flow into every 

 organ from a full, fresh, energizing source. " The perfect 



