The external causes, which may produce headache, are exceedingly numerous. It will only be necessary to enumerate a few, with the prominent remedies, under their respective heads.

When produced by a,fall, or blow: Arnica.

From abuse of spirituous liquors: Carb.-v., Nux-v., Coff., Pulsatilla.

From a chill: Bell., Bry., Dulc.,, Nux-vom.

When produced by bathing: Ant., or Pulsatilla.

From cold drinks: Bell., Ars., or Pulsatilla.

From changeable weather: Bry., Rhus, Carb.-v., Nux-v., Rhododendron.

From Tobacco: Ant., Ign., Aconite.

From prolonged watching: Cocc, Nux-v., Pulsatilla.

From heat: Acon., Bell., Bry., Carb.-v.

Dose

In sudden and violent attacks of headache it may be necessary to give the remedy once in from half an hour to two hours. Where it is long-continued or habitual, a dose may be given every night, changing the remedy, if after five cr six doses but little benefit has been derived.