of the bowels are contracted by an electrical virtue, which passes off, and disappears for a time, upon the touch of non-electrics? Or may we suppose, that such touches stop subtle vibrations in the small parts of the fibres?
Sixthly, Since vomiting is excited by disagreeable and painful impressions in the stomach, and requires the contraction of the diaphragm, and abdominal muscles, it agrees well with the notion, that sensory vibrations run into the neighbouring muscles for contracting them. I suppose also, that both orifices of the stomach are strongly contracted, previously to vomiting; and that the upper orifice, being most sensible, is contracted most strongly. Hence its power of contraction may be soon exhausted, and consequently it may open of itself in the action of vomiting. However, it may, in some cases, require to be forced open by the superior action of the diaphragm, and abdominal muscles. Almost all great pains and disorders in the lower belly occasion vomiting; which is very agreeable to the foregoing notion.
The nose itches, the mouth flows with water, the lower lip trembles, both are pale, and the person yawns, previously to vomiting, in many cases; all which things favour the notion of vibrations running freely along the surfaces of membranes.
Ructus, or the expulsion of wind from the stomach, is nearly related to vomiting, differing rather in degree than kind. Its suitableness therefore to the theory of these papers must be judged of from what has been advanced concerning vomiting.
The hiccough is also related to vomiting. It is supposed to proceed from an irritation at the upper orifice of the stomach, causing a sudden contraction of the diaphragm, so as to pull down the pharynx and larynx after it. May it not rather be a sudden contraction of the inferior or small muscle of the diaphragm only? This is particularly near the supposed seat of irritation; and upon this supposition, sneezing, surprise, and all other methods of making the whole diaphragm act together strongly, would remove it, as is observed in fact.
Seventhly, Permanent spasms, and violent motions, in the bowels, arise in consequence of uneasy and painful impressions there from indigested aliment, acrid fæces, irritating purges, poisons, &c. They are generally attended with the fermentation of the contents of the bowels, and the consequent generation of air; which, when confined by a spasm on each hand, distends the intermediate part of the bowel often to an excessive degree, causing a proportional degree of painful vibrations. If we suppose these vibrations to check themselves all at once, by occasioning a sudden contraction in the affected membrane, they may be propagated over the whole nervous system instantaneously, and give rise to the convulsion-fits, which happen to young children from gripes, and distention of the stomach and bowels, and to adults, from poisons, &c. This is upon supposition, that neither spasm gives way: for, if either does, the pain goes off, for a time at
