Fig. 29. The position assumed when the seat is of proper height, and the feet supported.
Fig. 30. The position a child naturally assumes when the seat is so high that the feet are not supported.
134. What is said of the benches or chairs in a school-room? What is represented by fig. 29? By fig. 30? What is the effect when the lower limbs are not supported?
135. Compression of the chest should be avoided. In children, and also in adults, the ribs are very flexible, and a small amount of pressure will increase their curvature, particularly at the lower part of the chest, and thus lessen the size of this cavity. The lower ribs are united to the breast-bone, by long, yielding cartilages, and compression may not only contract the chest, but an unseemly and painful ridge may be produced, by the bending of the cartilages, on one or both sides of the sternum.
Fig. 31.
