But there are those whose every farthing is needed to supply themselves with necessary clothing, their unfortunate parents, or orphan brothers and sisters with a subsistence. And forever sacred be these duties. Blessings be on the head of those who faithfully discharge them, by a cheerful sacrifice of selfish gratification. Cheerful, did I say? Ah! many will bear witness to the pangs which such a sacrifice costs them. It is a hard lot to be doomed to live on in ignorance, when one longs for knowledge, "as the hart panteth after the water brook." My poor friend L.'s complaint will meet an answering thrill of sympathy in many a heart. "Oh, why is it so?" said she, while tears ran down her cheeks. "Why have I such a thirst for knowledge, and not one source of gratification?" We may not know _why_, my sister, but faith bids us trust in God, and "rest in his decree,"--to be content "when he refuses more." Yet a spirit of _true_ contentment induces no indolent yieldings to adverse circumstances; no slumbering and folding the hands in sleep, when there is so much within the reach of every one, worthy of our strongest and most persevering efforts. Mrs. Hale says,-- "There is a charm in knowledge, _best_ when bought _By vigorous toil of frame and earnest search of thought_." And we will toil. Morning, noon, and evening shall witness our exertions to prepare for happiness and usefulness here, and for the exalted destiny that awaits us hereafter. But proper attention should be paid to physical comfort as well as to mental improvement. It is only by retaining the former that we can command the latter. The mind cannot be vigorous while the body is weak. Hence we should not allow our toils to enter upon those hours which belong to repose. We should not allow ourselves, however strong the temptation, to visit the lecture-room, &c., if the state of the weather, or of our health, renders the experiment hazardous. Above all, we should not forget our dependence on a higher Power. "Paul may plant, and Apollos water, but God alone giveth the increase." * * * * * _Ann._ Isabel, before we commence our "big talk," let me ask you to proceed upon the inference that we are totally ignorant of the subject under discussion. _Ellinora._ Yes, Isabel, proceed upon the _fact_ that I am ignorant even of the meaning of the term _physiology_. _Isabel._ It comes from the Greek words _phusis_, nature, and _logia_, a collection, or _logos_, discourse; and means a collection of facts or discourse relating to nature. Physiology is divided, first, into Vegetable and Animal; and the latter is subdivided into Comparative and Human. We shall confine our attention to Human Physiology, which treats of the organs of the human body, their mutual dependence and relation, their functions, and the laws by which our physical constitution is governed.