THE NERVOUS SYSTEM 251 



65. Effects of Alcohol upon the Brain. The brain under the 

 influence of small and occasional doses of alcohol shows no 

 serious changes other than an increased supply of blood to the 

 head. Very serious changes, however, result from the habitual 

 use of alcohol ; the brain becomes harder and tougher than is 

 natural, and its cell elements show a wasting away, its sub- 

 stance appears shrunken, and an undue amount of watery fluid 

 fills the cavities in the brain, in order to make up the dimin- 

 ished bulk. The blood-vessels of the brain are sometimes 

 found to be in a weakened condition, and from this various 

 cliseased conditions may follow. (Bead Note 13.) 



result proved ; and what is more curious still, the process was very 

 much shorter than any of his previous trials." W. B. Carpenter on 

 Unconscious Action. 



12. The Mind should be Intelligently Cultivated. " The cultivation 

 of the mind should be carried on with judgment, and in due submission 

 to the requirements of the body. If study be the duty of the youth, let 

 him pursue it diligently, but with such intervals of rest and bodily exer- 

 tion as may maintain good appetite and health. - 



"The proportion of hours of study and bodily exercise may vary with 

 the degree of mental work, the healthfulness of the room and surround- 

 ing air, the natural strength of the body, and the degree of health ; but 

 as a general rule it may be doubted whether any young person can sit at 

 close study for more than two hours at a time without requiring bodily 

 exertion to sustain vital action, and rest to recruit the mind. Two hours' 

 mental work, and a quarter to half an hour's bodily exercise, will be 

 quite compatible with the greatest progress in study. 



" Moreover, it may be doubted whether such a student can work with 

 advantage for more than eight hours a day, in addition to the intervals of 

 rest, for the issue will not turn on the number of hours devoted to work, 

 but the intensity of the attention given. " Edward Smith on Health. 



13. Trembling due to Alcohol " Another condition is trembling due 

 to alcohol. The hands are shaky, or unsteady, even when at rest, or if 

 the hand is held out it is seen to vibrate slightly, or in more advanced 

 condition, ' shakes like an aspen leaf.' I have seen this in a spirit-drinker, 

 a barber, as almost the only symptom : he worked night and day, in shav- 

 ing, and to ' steady his hand,' partook repeatedly of spirits at first to 

 relieve fatigue and then, because he saw that if he discontinued, his hand 

 was too shaky to use the razor. Complete abstinence from alcohol and 

 strong coffee quite removed his tremblings and his desire for spirits." 

 Dr. W. 8. Greenfield. 



66. How is the brain changed by alcohol f 



