Among the most important changes that occur in the nervous system is its gradual loss in power to respond to new demands. New habits are difficult or impossible to form, and old habits are hard to break. Attempts to break the habits of a life time are therefore dangerous, and radical changes in old people's ways of living are attended by risk as well as by unhappiness. Such loss of adaptability in the nervous system makes it increasingly difficult for old people to assimilate new ideas and to understand new points of view. The feeling that the world is strange and that the next generation has gone on without them accounts for the tragic loneliness of many old people. Clearly it is for those who are younger and more flexible to bridge the gulf between the generations by their understanding and their sympathy. Physical care to whatever extent it is needed should be given to all old people as soon as they are unable to care for themselves, and thought should be given to adapting their surroundings and ways of living to their strength and needs, just as they should be adapted to the strength and needs of chronic patients. But a warning should be given against managing old people too much. It is hard for people who have managed their own lives successfully for many years to be managed, even for their own good. Indeed, it is questionable kindness to deprive old people of all freedom of action, even if following their own inclinations occasionally has disastrous results. Few persons would wish to prolong their lives if long life involved being thwarted in every desire, and sometimes real kindness consists in allowing old people to do certain things that are not good for them. Keeping them warm and letting them do as they please will go far to make old people happy. Many of the changes in old age reverse the developing process of childhood. In youth and age extremes meet, and the care of the aged presents certain marked similarities to the care of little children. Both require simple food, occupations suited to their strength, and protection from infections, from fatigue, and from nervous strain; both are dependent, more or less helpless, and for their happiness both need the affectionate care of their own families. But in one respect their needs are fundamentally different. In childhood formation of proper habits is all important, and in caring for children the future effect of every word and act must be taken into consideration. Old people, on the other hand, since they live largely in the past and their habits are irrevocably formed, may be indulged without harm in ways that would demoralize a child; with a clear conscience one may make them happy in ways both great and small. This difference makes possible one of the greatest pleasures that come to one who cares for the helpless and the sick, for of all enduring satisfactions few are greater than the power to fill with comfort and happiness the closing days of life. EXERCISES