He glanced up at a flamboyant poster which Mrs. Clyde, who had a natural gift of draftsmanship, had made in a spirit of mischief, entitling it “The Red Nose as a Danger Signal.” “As much truth as fun in that,” he remarked. “But, at the best, we can’t live among people and avoid all danger. In fact, avoidance is only the outer line of defense. The inner line is symbolized by a homely rule, ‘Keep Comfortable.’” “What’s comfort to do with keeping well?” asked Grandma Sharpless. “What are your nerves for?” retorted Dr. Strong with his quizzical smile. “Young man,” said the old lady plaintively, “did I ever ask you a question that you didn’t fire another back at me before it was fairly out of my mouth? My nerves, if I let myself have any, wouldn’t be for anything except to plague me.” “Oh, those are pampered nerves. Normal nerves are to warn you. They’re to tell you whether the little things of life are right with you.” “And if they’re not?” asked Mr. Clyde. “Why, then you’re uncomfortable. Which is to say, there’s something wrong; and something wrong means, in time, a lessening of vitality, and when you let down your body’s vitality you’re simply saying to any germ that may happen along, ‘Come right in and make yourself at home.’ “Perhaps you remember when the house caught cold, how shocked Grandma Sharpless was at my saying that colds aren’t caught in a draft. Well, they’re not. Yet I ought to have qualified that. Now, what is a draft? Air in motion. If there is one thing about air that we thoroughly know, it’s this: that moving air is infinitely better for us than still air. Even bad, stale air, if stirred vigorously into motion, seems to purify itself and become breathable and good. Now, the danger of a draft is that it may mean a sudden change of the body’s temperature. Nobody thinks that wind is unhealthful, because when you’re out in the wind—which is the biggest and freest kind of a draft—you’re prepared for it. If not, your nerves say to you, ‘Move faster; get warm.’ It’s the same indoors. If the draft chills you, your nerves will tell you so. Therefore, mind your nerves. Otherwise, you’ll become specially receptive to the coryza germ and when you’ve caught _that_, you’ll have caught cold.” “I wish,” remarked Mr. Clyde, “that my nerves would tell me why I feel so logy every morning. They don’t say anything definite. It isn’t indigestion exactly. But I feel slow and inert after breakfast, as if my stomach hadn’t any enthusiasm in its job.” “Breakfast is the only meal I don’t have with you, so I don’t know,” replied the Health Master, who was a very early riser. “But I should say you were eating the wrong things, perhaps.” “How could that be?” said Mrs. Clyde. “Tom has the simplest kind of breakfast, and it’s the same every day.” “Well, there you are.” The Health Master’s tone assumed that the solution was found. “Where are we?” queried Mr. Clyde. “I’m up in the air!” “What is this remarkably regular breakfast?”