A corresponding capability exists in the drug, of producing an individual, although artificial, disease, which we recognize through the same method of observing the phenomena produced after the administration of the drug. The power to produce these phenomena is what we call the properties of the drug. It is the characteristic of disease to produce certain phenomena which are not observable in perfect health. It is only through the observation of these expressions that we can make any use of the law of cure, and there can be no general consideration of the rule of cure unless it comprises a consideration of symptoms as one of the necessary elements. One might say that a comprehension of the symptoms of a given case was one of the primary factors, and in so far as one comprehends the expression of disease in these phenomena is one equipped to follow the law of cure in any particular case.
Symptoms are the only representative expression of the diseased state.
We include sensations as expressed by the patient, the appearances in all parts of the body, the varied circumstances under which these symptoms were recorded, and the varied grouping of these symptoms, in any consideration of the case. When a symptom is noted under certain circumstances and not under others, this obvious relation between the symptom and its related circumstance is in itself a symptom, or rather, a part of the symptom, the sensation being quite incomplete without the expressed relationship of circumstance. Very often the concomitant of circumstance is of greater importance to the whole case than the expressed sensation, but sensation is much more frequently expressed by the patient. Two or more symptoms may appear together, or synchronize with each other, so frequently that they are really one symptom and must be considered as such in our analysis. As nothing in nature can be represented by a single property, so no disease can be represented by a single symptom.