But any changes of this sort should be gradual; as those which are _sudden_, are trying to the powers of the stomach, by furnishing matter for which its gastric juice is not prepared. In regard to the nature of the meals prepared, the breakfast should furnish a supply of liquids, because the body has been exhausted by the exhalations of the night, and demands them more than at any other period. It should not be the heartiest meal, because the organs of digestion are weakened by long fasting, and the exhalations. Dinner should be the heartiest meal, because then the powers of digestion are strengthened, by the supplies of the morning meal. Light and amusing employments should occupy mind and body for an hour or more after a full meal. But little drink should be taken, while eating, as it dilutes the gastric juice which is apportioned to each quantity of food as it enters the stomach. It is better to take drink after the meal is past. Extremes of heat or cold are injurious to the process of digestion. Taking hot food or drink, habitually, tends to debilitate all the organs thus needlessly excited. In using cold substances, it is found that a certain degree of warmth in the stomach is indispensable to their digestion; so that, when the gastric juice is cooled below this temperature, it ceases to act. Indulging in large quantities of cold drinks, or eating ice-creams, after a meal, tends to reduce the temperature of the stomach, and thus to stop digestion. This shows the folly of those refreshments, in convivial meetings, where the guests are tempted to load the stomach with a variety, such as would require the stomach of a stout farmer to digest, and then to wind up with ice-creams, thus destroying whatever ability might otherwise have existed, to digest the heavy load. The fittest temperature for drinks, if taken when the food is in the digesting process, is blood heat. Cool drinks, and even ice, can be safely taken at other times, if not in excessive quantity. When the thirst is excessive, or the body weakened by fatigue, or when in a state of perspiration, cold drinks are injurious. When the body is perspiring freely, taking a large quantity of cold drink has often produced instant death. Fluids taken into the stomach are not subject to the slow process of digestion, but are immediately absorbed and carried into the blood. This is the reason why drink, more speedily than food, restores from exhaustion. The minute vessels of the stomach inhale or absorb its fluids, which are carried into the blood, just as the minute extremities of the arteries open upon the inner surface of the stomach, and there exude the gastric juice from the blood.