134. _The benches or chairs for children in a school-room should be of such a height as to permit the feet to rest on the floor._ If the bench is so high as not to permit the feet to rest upon the floor, the weight of the limbs below the knee may cause the flexible bone of the thigh to become curved. The child thus seated, is inclined to lean forward, contracting an injurious and ungraceful habit. Again, when the feet are not supported, the child soon becomes exhausted, restless, and unfit for study. In the construction of a school-room, the benches should be of different heights, so as to be adapted to the different pupils, and they should also have appropriate backs. [Illustration: Fig. 29. The position assumed when the seat is of proper height, and the feet supported.] [Illustration: 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. [Illustration: Fig. 31. A natural and well-proportioned chest.] [Illustration: Fig. 32. A chest fashionably deformed.] -=-=-=-=-=-=-=-=-=-=-=-= 135. Why should compression of the chest be avoided? What is represented by fig. 31? By fig. 32? -=-=-=-=-=-=-=-=-=-=-=-= 136. Again, the cartilages on one side may be bent outward, while those on the opposite side are bent inward, thus forming a depression parallel with the sternum. In some instances, the anterior extremity of the lower ribs on each side are brought nearly or quite together. In these instances, the movable extremities of the ribs are drawn down toward the haunch-bones, while the space between the ribs is lessened. All this may be effected by tight or "snug" clothing. Therefore the apparel of a child should be loose, and supported over the shoulders, to avoid the before-mentioned evils. The same may be said of the clothing for adults.