A. P. Davis, M.D., N.D., D.O.
    This phrase means "The Science of Diseases"; that is, the knowledge of the difference between a healthy and an unhealthy condition of the body.

    The various conditions, called disease, are affections which are different from a natural or a normal state. "The change of a normal to an abnormal condition," is the most appropriate way of expressing it. The changes take place in the body anywhere. Disease may be local in its nature and effects, or it may be general, affecting the entire body. Disease means "want, or lack of ease." It may be characterized by severe, or a modified uneasiness in a part. The manifestation of pain or uneasiness, anywhere in the body, is an indication of local or general disturbance of the nervous system. The term Nosology means, a classification of diseases, or naming them. The name usually indicates the locality it is found to affect, the organ or tissue; or the location of the pain, heat, redness or swelling perceived by the person or the observer. The classification is made with regard to the nature of the structure involved.

    The term Sciatica, for instance, indicates that the diseased nerves in the sciatic arc are involved - inflamed or irritated - to that extent that they become painful. The disease may be a result of impeded venous circulation in a part of the body or limb, and press upon small nerve filaments, and these filaments may end in muscular tissue, and interfere with arterial circulation of the blood in the capillaries; and the blood may accumulate and press upon other nerve filaments, and a condition called congestion of blood takes place, and disease results. Diseased conditions are the product, or the consequence, of nerve disturbance, either primarily, or secondarily; for the nervous system is the medium through which all control of the body is affected and any disturbance of the nervous system may cause pain, or disease, or a change from a normal to an abnormal condition. Thus the reader can readily understand that disease is not an inherent state, or a normal condition of the body, but a product of nerve disturbance. The disturbance of the nervous system may be a result of various causes, and the nerves may be affected anywhere, at their origin, or at their terminals, and to any degree.

    The disturbance may be simply a slight irritation, a strong pressure, or a destruction of the nerve itself. The result will be, as a general thing, in accordance with the amount of injury or disturbance of the nerves involved; for the nerves express themselves at their endings, and the organ in which they end; they express themselves, and the degree of function, and the kind of function has much to do with the result of the disturbance.

    The various conditions and modifications, and varieties of conditions, called disease, seem to be the stumbling-blocks over which many fall and wonder why certain conditions are to be treated differently from other conditions, or no effect need be expected, as to the amelioration. While it is a fact that certain conditions require special attention, different from some other conditions, known as disease, many are puzzled on account of the reason therefor.

    The majority of physicians have but few remedies they prescribe, yet they treat many conditions with these few medicines. The better informed physicians treat the patient for the purpose of restoring the harmony, and for the purpose of bringing about certain conditions in the body, and rest results when these conditions are brought about. Whilst they may have specifics for certain conditions, they have no specifics for what is commonly denominated disease. There are certain conditions which indicate a change for the better, and these are what the physician seeks to bring about by his medication; and when that is accomplished, he is satisfied that the diseased condition is subdued and will terminate favorably.

    The physician who treats "disease" is unsuccessful, for there is no relationship between disease and medicine. Conditions are the things to consider always.

    If one has a fever, it is due to disturbance of the nervous system, and the circulation of the blood is interfered with, and is a prominent factor in producing the condition. Hence, the attention should be directed to a restoration of the normal circulation of that element; and when that is accomplished, the fever - the effects cease. When there is inflammation anywhere in the body, it is always due to impeded venous circulation where the manifestation is expressed - or with the vessels leading from that place which carry the fluids back to the heart - and these are the veins. They being free the trouble is over and a return to a normal condition ensues as fast as the congestion is dispelled.

    These are the general principles of treating all pathological conditions called disease. There are three conditions which exist in all pathological conditions. These are invasion, retention, enervation, and these constitute every known condition we have to combat in order to free the system from disease. All of these conditions may be found in all diseases known to humanity, and are what we have to consider. It seems to be unnecessary to pay any attention to the names of conditions called disease, after considering the foregoing statements of facts; for we have to do with conditions which must be changed before diseases, so-called, can be removed; that is, what is regarded as special affections in various forms and localities throughout the body. To be specific and direct, the reader's attention to what must be done, seems sufficient for all who make this science a study.

    Inasmuch as all conditions are products of nerve-waste - nerve irritation - nerve disturbance in some way, it seems plausible to assume that when we remove the causes of the disturbances, wherever found in the body, we have done all that is necessary to do - all that nature demands.

    The various ways recommended in the body of this book will be sufficient to accomplish all that can be accomplished, and the one who applies the principles thereof intelligently and understandingly, will find his efforts, generally, satisfactory. The philosophy is correct, and the science, when applied comformably thereto, will prove a boon, satisfactory to both patient and physician.

    The several methods of applying the means to right the wrongs, are specifically given, and the philosophy is understood, there should be no difficulty in applying it.