Symptoms which return at stated times become important in proportion as the sickness of which they form a part diverges from the malarial type or is not connected with naturally periodical functions.
A few remedies have such a remarkably exact periodicity as to distinguish them from among all the ordinary anti-periodics, but in spite of this, they have not been found to be even as frequently useful in intermittents as many others having a much less marked periodicity. They are more suited to erratic forms of malaria, such as malaria neuralgias, etc. Aranea, Cedron and Sabadilla seem to hold the chief rank among them.
There are certain other remedies which exhibit their action during a more or less definite time of the day; among the most prominent are Natrum mur., 10-11 a.m; Belladonna, about 3 p.m.; Apis, 3 to 5 p.m. and the well-known Lycopodium from 4 to 8 p.m.
The different divisions of the day have a large number of medicines each, from among which a few stand out prominently. We have Pulsatilla in the evening; Rhus tox. and Arsenicum right after midnight and many more.
The action of some medicines coincides with the time periods of the sun, moon or the seasons, and thus affords peculiar differentiations by which we may pick them from among others. That drugs may also exhibit cycles of action corresponding to other planetary influences seems very reasonable but has as yet not received much attention.
Many plants are known to show certain manifestations at particular hours of the day. According to the doctrine of signatures they have a meaning for us if we are only wise enough to see and use them. When we bear in mind that the universe moves forward in obedience to laws which work harmoniously and that every part thereof bears a definite relation to every other part, no fact however insignificant remains without value. Such things are the little hints thrown out to attract our attention, the rest we must do for ourselves.