We have here at our disposal a marvelous and complicated machine, perfect in design, and imperfect only through some inherited fault or weakness of our ancestors. Most of its processes are automatic, though some are deliberate, or voluntary. The automatic processes themselves may fail to operate, however, through some carelessness of our own in details that we must attend to of our own will. When the voluntary processes are continued with great regularity, they become so habitual that they may be considered almost automatic themselves, and in this state of affairs the whole machine is operating to the best advantage, and will receive no injury except from some outside cause. This wonderful machine must breathe—an involuntary or automatic action—but it must have pure and wholesome air, day and night, which is to be made sure only by our own care and voluntary action. It must be well nourished by proper food, obtained, selected and prepared by our own voluntary effort, but the food then is assimilated into our strength and support by the automatic and involuntary processes of digestion. So it is through a long list of details which might be named, that the machine of our body is kept in running order—in health, as we say—by a combination of voluntary and involuntary processes, the latter depending on the former in high degree for their success. All of these details are simple enough in themselves when studied a little. In normal and wholesome surroundings, such as, fortunately, most people in this country enjoy, it is an easy matter to avert disease by proper care, and to bring the system into such condition that in the event of sickness the ailment can be thrown off readily by proper attention. Carelessness of habits not only makes the individual more liable to the outbreak of disease, but weakens the power to combat the disease after it has once gained a hold. This chapter is not primarily a medical work in the general use of that term. That is to say, it does not go into the scientific and technical details of physiology, nor yet the description and treatment of every disease, simple or otherwise. Until all persons are educated in disease and medicine, the very best advice that can be given in the event of serious illness is—Call a competent, progressive, educated physician as promptly as possible, and yield absolute obedience to his instructions and treatment. But these instructions will include details of nursing and diet, general care of the health, and other things which are of great importance in assisting the work of the doctor. He will welcome the evidence of knowledge of such things which can be gained from this practical book. Furthermore, for an intelligent understanding of the human body, how to keep it in health, and how to treat its simple ailments, and the emergencies of all sorts that demand quick attention, this department of the present work is confidently offered to the reader.