He would take his meals at any time that happened to be convenient, and would eat anything that came before him, regardless as to whether it suited him or not. Furthermore, he often ate to repletion, and bolted his food down without masticating it properly. And that was why his own machinery ran badly and he felt tired and depressed. In which respects he was exactly like thousands of other people. This resemblance between a steam engine and the human body is a pronounced one. As we have already pointed out, the food, after being digested and absorbed through the walls of the digestive tract, is burnt up in the tissues by a process closely corresponding to that of ordinary combustion, and there is a residue of waste products left behind resembling the cinders and ashes of a coal fire. Nature is able in various ways to dispose of this waste, eliminating it from the body. If, however, the amount of food taken be excessive, the residue is so large that the resources of the system are not sufficient to cope with it, and in consequence it accumulates in the tissues. Then the individual suffers from discomfort or pains in the muscles, and from headache with a sense of tiredness, even apart from exercise or work; also from various other symptoms, owing to this waste matter circulating in the blood. The wrong sort of food may have been taken, or eaten either too quickly or at unsuitable times, and dyspepsia results. Then there is a certain amount of undigested food constantly left behind in the stomach, and this begins to ferment, developing a poison of its own, which gets into the circulation and aggravates the effect of that already present. At the same time the nutritive quality of the food is diminished, so that there is superadded a process of starvation. There is plenty of food, but little nourishment. The final stage is therefore one of poisoning and inanition combined. The effect of this on the whole body, and especially on the nervous system, is harmful to the last degree. The headaches are accentuated, and the individual feels depressed and irritable. The irritating influence of these baneful products is so marked, that the different organs begin to show signs of the damage which is slowly but surely taking place, and the delicate nervous system feels the influence of it most of all. The pain, discomfort and nausea caused by the contact of acid undigested food with the lining of the stomach add to the feeling of misery. This may go on for years, until with one thing and another life is hardly worth living. It may disappear for a time, only to return, perhaps, in an aggravated form. Meanwhile the strain on the whole organisation becomes greater, as the organs grow less capable of propping each other up. If it is allowed to continue indefinitely, the time may come when Nature will rebel, refusing to be treated in this scurvy manner any longer.