In every case, the first object should be to ascertain and, if possible, remove the cause of a disease. It should be remembered that medicinal substances are always more certain in their action when applied directly to the affected tissue; also, that chemical, physical and vital changes result from the topical action of such substances; and that age modifies the effects, and also determines the dose; also sex, owing to the greater susceptibility of the nervous system in females than in males; also the temperament, as the sanguine, for example, is more susceptible to the influence of medicinal agents than the phlegmatic; also habit and mode of life, as the habitual use of such agents as stimulants lessens their influence, and the occupation affects the susceptibility to external influence; also the condition of the body, as different diseases exercise considerable influence on the effects of medicinal substances; also the mind, as a hopeful mind conduces to the beneficial action of medicines; also idiosyncrasy, as some individuals are more susceptible to the action or effects of medicinal substances than others; also the nature of the tissue or organ to which application is made, as some are more susceptible to the effect of medicinal agents than others, owing to rapidity of absorption and the degree of decomposition of the substance employed; also climate, from the recognized influence of climate in modifying the structure and functions of the animal economy, and increasing or diminishing morbid conditions, and by such means influencing the effects of medicinal-agents.

In most acute diseases there is a tendency to recovery after a certain time has elapsed, in case there is no failure in the functions of any of the essential organs; hence, in all acute diseases, the state of the nervous system should be carefully watched.

When the affection is not of a serious character, such symptoms as are especially troublesome may be relieved; but when the nervous and vascular systems are affected, both locally and generally, then it is necessary that the proper measures for their relief be promptly taken.

Where mucous membrane is the seat of the affection, it is often possible to remove the exciting cause. There are also many inflammatory affections met with, where, from the beginning, there is a diminished action of the heart, and a depressed state of the nervous centres. In the treatment of such cases, the depressed condition of the general system chiefly requires attention, as the progress and termination of the local affection depend upon the cause from which it has originated.

There are also morbid states not necessarily dependent on organic disease. Various acids are produced by the fermentation of substances containing starch or sugar, and there is reason for believing that an increased secretion of acid may take place from the mucous membrane of the stomach and produce symptoms of acidity independently of fermentation, although one of the properties of the gastric fluid is to prevent fermentation. The symptoms of acidity are a sour taste, and the occurrence of acid eructations, often accompanied with heartburn, and sometimes with diarrhoea, and a feeling of sinking at the epigastrium.

In these cases the causes must be sought for, and such treatment instituted as will neutralize the acidity and stimulate the peptic glands to an increased secretion of the digestive fluid; also such as will regulate the bowels. Due attention must also be given to the diet, which should consist of such substances as will not readily ferment, and all food containing starch should be avoided.

Although topical remedies are more generally employed in the treatment of dental affections, yet there are many diseases of the oral cavity which are due to remote causes and require constitutional as well as local treatment.

The appearances presented by the mucous membrane of the mouth are valuable, as indicating the state of other parts more remote; and it is frequently the case that, when the constitutional affection is overcome, the local symptoms disappear as a consequence, or become very amenable to local remedies.