PRACTICAL QUESTIONS.--=1.= State how in the case of a person with round shoulders a gradual remolding of cartilages (which ones?), the strengthening of the muscles (which ones?), and the practice of deep breathing may each contribute toward acquiring an erect and perfect figure. =2.= Should a hat be well ventilated? (A punch for making the holes costs a dime.) Should a hat be stiff or soft? =3.= Name habits that impair the power of the lungs. =4.= How could you convince a person that a bedroom should be open while and after it is swept? That it should be ventilated at night? =5.= Which is the more injurious to others, tobacco chewing which causes the ground to be unclean, or smoking which renders the air impure? =6=. Why do those who stand straight up to hoe not get tired half so quickly as those who bend or “hump” over? (Chap. VI.) =7.= Why do students who sit in rocking chairs, or from other causes lean the head forward when they study, often find that they recover from drowsiness if they sit erect, or sit in a straight chair? =8.= How are high collars a fruitful source of bad colds? =9.= If the draft up the chimney of the fireplace, when the fire is burning, takes up a volume of air sufficient for many people, why is it unnecessary to open a window? =10.= Why does cold impure air make a person colder than cold pure air? (p. 14.) =11.= Do the modern customs of uniformity in dress for all classes and climates, shipping foods from great distances, one section or nation imitating the ways of another section or nation, lead toward health or disease? Do such customs violate or conform to the great biological law that life is a process of adaptation to environment? [Illustration: FIG. 87.--SUSPENDERS should have a pulley or lever at the back, that the strap on one side may loosen when one shoulder is raised.] [Illustration: COLORED FIGURE 6.--ORGANS OF THE TRUNK. _cb_, collar bone; _r_, ribs; _z_, tongue bone (hyoid); _k_, _k_, cartilages of larynx; _l_, windpipe; _s_, thyroid gland; _rv_, right ventricle; _lv_, left ventricle; _ru_, right auricle; _lu_, left auricle; _a_, aorta; _ka_, artery to head (carotid); _sa_, subclavian artery; _la_, pulmonary artery; _oh_, superior vena cava; _hv_, jugular vein; _lu_, lungs; _f_, diaphragm; _lb_, liver; _g_, gall bladder; _s_, stomach; _x_, spleen; _n_, mesentery with vessels; _d_, small intestine; _gd_, large intestine; _b_, cæcum; _w_, vermiform appendix; _h_, bladder.] CHAPTER VII FOOD AND DIGESTION _Experiment 1._ =Tests for Acid, Alkaline, and Neutral Substances.=--Repeat tests described in General Introduction.[6] [6] See also Peabody’s “Laboratory Exercises in Physiology,” Holt, N.Y. _Experiment 2._ =Test for Starch.=--See General Introduction. _Experiment 3._ =Test for Grape Sugar.=--See General Introduction. _Experiment 4._ =Test for Proteid.=--See General Introduction.