পাতা:পদার্থবিদ্যাসার.djvu/৮৩

72 great pillars of a building; the muscles, or the fleshy parts, as so many cords to bring every thing into inotion ; the arteries and veins, as the streams of refreshment and the springs of life. The heart, in the middle, as the fountain or working machine, conveys the blood by measts of the arteries to the extremities, which is returned back by the veins; and the continual pulsation of the heart keeps up the perpetual circulation of the blood. The lungs are instruments to admit good air to cool and refresh the blood, and to jet the air out when it has performed its office. The stomach is a great laboratory, where every thing is prepared that can serve to the necessary recruiting of the whole body. The arms, hands, and fingers may be considered as the guardians of the body, the house, and are meant to labour in the various duties of life; the fingers are therefore formed with small bones and strong muscles, to move with the greater ease. Pup. Is the right hand forined with more or stronger muscles than the fest ? Tut. No ; that we can do more with the right land is only owing to habit, inecause we have been accustomed from our infancy to use that unore than the left. * * Pup. Have yoa any thing more particular to observe here 2 Tut. It is worth attention to remark, that the skin of the hand becomes thicker, that it may not be worn out by working, and yet does not entirely lose its seeling.” The same nay be observed of the soles of the feet. The position of the thumb also gives ad