“Yes,” I said, as I bade her good-bye, “but not excitedly, Esther; and remember what I said about night air, damp feet, and warm clothing.” There was a little impatient toss of the head, and just about half a frown, and I smiled, expecting her to say, “Oh, bother!” but she did not. Well, poor Esther died. But I know of nothing more sad when one is ill than the thought that the illness might have been avoided. “I wish I had been more careful.” If you let your thimble fall, it will drop to the ground, will it not? This is a law of Nature; and as sure and certain is every other law of Nature. Nature will forgive, but she never will forget. If you, for example, sit in wet clothes, evaporation takes place; in other words, the damp of your clothes passes off in steam, and, as water requires so much heat to convert it into steam, it takes this heat from the nearest source, and that is from your body. It absorbs animal heat. What is the consequence? Why, baby there could understand this simple lesson in physiology. The consequence is that the surface of the body becomes chilled. Well, then another law of Nature comes into force. The law is this: Cold contracts. Cold contracts everything, even iron. Witness the difference in the length of railway iron rails in summer and winter. Given a sun-heat of, say, one hundred and twenty degrees, and they are all close together at the ends. Given a winter temperature of thirty-two degrees, or under, and the rails do not touch, but gap. And the cold on the surface of the body contracts the veins and arteries. With what result? With the result that the blood is to some extent squeezed—to use simple language—out of them, and, as it must flow somewhere, it rushes in upon the internal organs of the body. Now, we all of us have some one organ weaker than the others, and it is this organ that suffers from a surfeit of blood in its veins, driven inwards by a chill. It may be Miss Ada’s liver, and she has in consequence “a horrid bilious attack,” as I have heard it called, or it may be worse, suppression of the bile entirely, followed naturally by blood poisoning and jaundice. It may be Miss Ada’s lungs. The blood is driven in upon the surface thereof; this surface becomes congested and red, though no one can see it. Nature tries to relieve the congestion by throwing off through the walls of the veins or arteries the watery portion of the blood. This tickles the lungs, and a cough is the result. But the very act of coughing increases the mischief tenfold, and what was at first water may become matter.