In the investigation of disease, to form a correct idea of its character and the treatment necessary to produce relief, there are several important points to be taken into consideration, aside from the symptoms as they casually present themselves to the eye.

The age and sex of the patient should be borne in mind, and the diseases most likely to occur in the successive stages of life should not be forgotten.

When man lives his appointed time, dying not of disease but of old age, there is a regular ascending scale up to a certain point, which turned, he commences the descending path of life. Each of these several stages or steps is characterized by certain peculiarities.

In the first period of childhood, extending to the time of teething, the little being is extremely susceptible to external influences, and liable to disease from the slightest causes. The whole nervous system is exceedingly sensitive and the little patient peculiarly liable to affections of the brain and spasmodic attacks. This period should be closely watched (see chapter on diseases of children.)

In the second and third stages, extending from teething to about the seventh and fourteenth year, there is a want of firmness in the fibre of the system, a susceptibility to fatigue and the consequent necessity of a larger amount of rest than in later years. There is a liability to affections of the brain and respiratory organs.

The next stage, extending to the twenty or twenty-fifth year, during which the system is approaching maturity, is one of the most important periods of our existence. 1*

It is during this period that the seeds of constitutional disease are most liable to ripen into a fatal harvest, and now when the passions are strongest, there is danger by their abuse of being thrown from a proper balance, into a too powerful exertion of the mind and body, thus sowing the seeds of diseases, which may be a torment in after life and end in early death.

After a person has reached the age of fifty-five or sixty years, he generally begins to feel that he is growing old; the functions of the body may become less active, and the mind, notwithstanding it may be equally strong, less active in its movements. As year after year rolls away, he is made aware in the stiffness of the joints, in the gradual blunting of the faculties of perception and sensation, that he is rapidly treading the downhill of life. During this stage, he is peculiarly subject to paralysis of various organs, deafness, blindness, apoplexy, asthma, etc. Constitution and temperament, are also important points of inquiry, a proper understanding of which will aid materially in the correct selection and administration of remedies. The cause of the disease should by no means be overlooked; the previous habits of the patient should be ascertained, and in cases of long standing, or when there is reason to suspect hereditary taint, the health of the parents, and even grand-parents, should be known, also whether at any time during the previous life of the patient he has been afflicted with either eruptions, or other diseases, which might not have been entirely eradicated from the system, or whether the medicines given might not have engendered other diseases more painful and lasting than the former. An understanding of the cause of the disease will often be a sure guide to the selection of the remedy.

Thus diseases resulting from contusions, sprains, etc. would indicate Arnica. In a rheumatic affection produced by dampness, or getting wet, we should think of Rhus. Affections produced by grief or chagrin would require Ignatia, while those occasioned by fear would indicate Opium. Diarrhoea occasioned by cold requires Dulcamara. Derangement of the stomach with nausea under certain circumstances would yield to Ipecac, but if the disturbance was occasioned by eating fatty food, the Ipecac. would be ineffectual and Pulsatilla be required.

The mind should also be directed to exposures to heat or cold, dampness, unhealthy air, food and clothing, miasmata, contagions, errors of diet, abuse of spirituous liquors, and the various causes which would have a tendency to produce disease.

Finally, the patient should be permitted to explain in his own words, his general sufferings, and the character and location of the pain. It should be ascertained whether the pain comes on at intervals, or is uninterrupted, how long it continues and whether it is worse during the day, or at night, what peculiar symptoms it is associated with; and such other questions, as will guide to an accurate knowledge of the disease. For directions as to the administration of remedies, see the following chapter.