Epilepsy and Hysteria are frequently inherited. This supplies us with one argument. They are also apt to be brought on by various depressing causes which affect the system in general. The strumous diathesis, which originates in the fluids, and not in the nervous system, is affirmed by Dr. Cheyne and Dr. Watson to be a powerful predisposing cause of Epilepsy. Hysteria, too, is very often associated with Anæmia. Tetanus even depends very much on certain atmospheric conditions. There are sometimes, as it were, epidemics of Tetanus, in which the slightest abrasion will suffice to bring it on among the people residing in a particular neighbourhood. It is often rife in one district a long consecutive time. Facts like this must certainly be regarded as pointing to a condition of the blood as one, at least, of the causes of this terrible disorder. This condition of the blood may react upon the nerves, and maintain in them a particular morbid state. Chorea seems also to depend primarily on the state of the blood, and is indirectly curable by medicines which, like Iron and Quinine, improve its condition. In a weakly and strumous child it may be brought on by a sudden fright which would not affect one of a good constitution. We might conclude from these facts alone that the blood is often the seat and origin of these diseases. But there is yet a stronger reason to induce us to suppose that they are frequently produced by some poison in the blood, which acts on and disturbs the nervous organs without perceptibly altering their physical construction. Many medicinal substances present us with an artificial illustration of this action. Lead, Copper, Mercury, and Arsenic, by their presence and operation in the blood, are capable of causing severe and chronic nervous disorders, particularly Paralysis and Epilepsy. Many of the vegetable Neurotics, after their passage into the blood, bring about transient nervous symptoms which are identical with those of disease. Thus Opium produces coma; Belladonna, delirium; Aconite and Hemlock, paralysis; Hydrocyanic acid, convulsions; Indian hemp, catalepsy. When the cause of these affections is removed, the symptoms disappear; when the cause returns, the symptoms return. The same is apparently the case with those unknown animal poisons that operate so as to produce nervous symptoms, without a nervous lesion. These convulsive disorders may be treated in either or both of two ways. We may attack the supposed cause in the blood by employing one of these mineral Anticonvulsives; or we may simply apply our remedies to the nervous system, the more immediate seat of the morbid manifestations, and adopt a palliative or defensive course.