must be recognised as a most potent predisposing cause. The great fact of mind or emotion is a powerful influence in producing, in preventing, or in curing disease.
This psychological side of medicine is only beginning to receive due attention. As the fallacies which arise in animal experimentation from the production of fear, pain, and coma have not yet been fully recognised, so the inevitable influence of mind in modifying physical conditions has never yet been studied scientifically in human medicine. Yet facts exist in unsuspected abundance which need to be collected, verified, tabulated, and their laws of action diligently studied.
It is known that even that strong muscle the heart may be ruptured by the agony of intense emotion. At Blackburn, the daughter of a woman charged with theft became dumb with horror at her mother's sudden arrest. Dr. Gayet, after vainly treating a very pronounced aneurism of the internal carotid artery, was proceeding to operate, when his patient suddenly recovered. Hydrophobia, cholera, and even small-pox, appear to have been caused by fear.
The extent to which even the so-called microbes
