SYMPTOMS (Gr. sympiplein, to concur), in medicine, are the morbid phenomena by which the physician becomes aware that derangements of some kind have taken place in the economy; but it requires a mental effort to convert these symptoms into signs of disease. A symptom thus converted into a sign of some special disease or disordered condition, tends to constitute the diagnosis, or recognition of the disease. " The inter pretation of symptoms," as Dr. Aitken observes, ' can only be successful after a close observation of the patient—often prolonged and repeated for more complete investigation —so as to connect the results arrived at with his previous history. The utmost logical acumen is required for the due interpretation of symptoms. The individual value of each ought to be duly weighed; one symptom must be compared with another, and each with all, while the liability to variation of a similar symptom in different cases of a like kind must not be forgotten. Thus only can the nature of a disease be clearly determined, its severity and dangers fully appreciated, its treatment indicated, and the probability of recovery foretole- "—The Science and Practice of Medicine, 3d ed. vol: i. p. 9. Many
writers, following the example of Laennec, confine the term symptom to the phenomena depending on vital properties; while those phenomena of disease which are more directly physical, they call signs. We thus have what may be called physical signs and vital" symptoms. The form, size, color, firmness or softness, beat and odor of a part of the body, the sounds which it yields on percussion or discultation, etc., afford physical signs; while vital symptoms may be exemplified in pain, uneasiness, altered or impaired sensations, spasm, vomiting, the accelerated pulse and hot skin of fever, the state of the tongue and of the alvine and urinary excretions, etc. The term semeiology (literally, the theory of signs) has been given by medical writers to the general study of this subject, which is admirably discussed in Williams's Principles of Medicine.