8. In all the operations of nature which we have access to investigate, the action of electricity is so much concerned, that we can scarce suppose it to be wanting in any of them. That it is concerned in preserving the health of the human body is likewise certain, if it be the fluid which acts in the nerves, as most probably it is. But whatever preserves health will also bring on disease, if it be applied to that purpose; and we have already seen that this fluid is capable of bringing on the most dreadful symptoms, viz. mortification in its highest stage, fever, convulsions, bilious discharges, lethargy, &c. If it be capable of producing all these, can we say that it is not capable of producing those of an inferior kind, or of varying diseases and symptoms without end, according to the immense diversity of its action? It may be said that this disease was occasioned by a violent stroke of electricity, similar to lightning; but how many people have declared, that, in the beginning of some violent epidemics, they have felt a sudden stroke at the time of seizure! Dr. Hodges mentions this in the plague of 1665 at London, but treats the accounts as effects of a distempered imagination. Procopius relates the same of the plague in his time, viz. that many of the diseased felt a stroke. It is true that they said such strokes were given by spirits in human shape, in which we know they must have been deceived; but, though they were mistaken in supposing that they had been struck by a spirit, it does not from thence follow that they felt no stroke at all. The people mentioned by Dr. Hodges did not say that they were struck by a _spirit_, yet he treats their accounts with as great contempt as though they had. Where people have no interest in deceiving, we ought certainly to look with a favourable eye upon their testimony; for, even although some part of it should be incredible, we have still reason to believe that there is some foundation for what they say. Thus, the poor sailor, so much frightened at the sight of a large bat in New Holland, was certainly mistaken in saying that he had seen the devil; he was even mistaken in saying that he had _horns_;[92] but from all this it would have been doing him great injustice to say that he had seen nothing. In like manner, when numbers of people in Procopius’s time said that they were struck by spirits, when we find others in Dr. Hodges’s time saying that they were struck by some invisible agent, when we know that electricity _can_ strike in an invisible manner, it certainly is more reasonable to conclude that violent diseases sometimes do begin by an electric stroke, than that _all_ who said they were struck in this manner were madmen or liars.