A long, rapid walk in the evening, as we all know, will produce the same effect. We return, and remark that we are hungry, merely meaning that we have received polite official notice that our physical bank account has been overdrawn. If we do not pay any attention to this notification, we shall surely in time be passed from adversary to judge, and from judge to officer, and finally be cast literally into a prison from which, unlike some of our city prisons, we shall not escape till we have paid the uttermost farthing. Then we shall be likely to receive from the kindly friend whom we summon to visit us, wise and good advice, on the extravagance of spending so much. But might not the advice be possibly quite as useful if delivered in this wise: "Why don't you earn more, and make larger deposits." The force of weakness compels us to stop spending our muscle cells; the kind friend, as far as is possible, puts a stop to the expenditure of nerve cells, and draws on the funds derived from the Cinchona forests of South America and the iron mountains of Missouri, to make new deposits on our account; and when the matter is thus doubly settled for us by nature and science, we go on our way rejoicing, only to repeat the same insane folly. But it is not good for one's credit to overdraw too frequently her bank account; and there may come a time when suspension means bankruptcy, and when all the kindness and skill of all our friends can be no longer of any avail. Is it not our own fault, and shall we not so educate our girls that they shall not fall into it, since they comprehend its unreason? We are undoubtedly creatures of habit; but we oftener apply the word to our mental and moral than to our physical nature, and wrongly. When regular and constant demands are made upon any organ of the body, the body, as it were, falls into the habit of laying in enough force in that particular department for that particular purpose, as the scientific steward at Vassar lays in for each day so many pounds of beef or mutton, because he can rely with certainty on its consumption. If in any case the demand is, for any reason, slackened, there is a surplus of energy which must find a vent, or render its possessor very uncomfortable. Need mothers be reminded of how very troublesome the little girl becomes in a short school vacation, or during the first days of a long one? Or need teachers be told that it is only a loss of time in the end, to assign at the commencement of the September term lessons of the same length as those which were learned with no difficulty in June? There is a decided inertia in the bodily functions, and time is required for a sudden change. Inconvenience in such a case will be sure to arise, unless the surplus force be instantly directed into other and unobjectionable channels.