potation of fermented liquor. So if a considerable part of a connected
tribe of action be disturbed, that whole tribe goes on with confusion, till
the part of the tribe affected regains its accustomed catenations. So
vertigo produces vomiting, and a great secretion of bile, as in
sea-sickness, all these being parts of the tribe of irritative catenations.

8. Weaker catenated trains may be dissevered by the sudden exertion of the
stronger. When a child first attempts to walk across a room, call to him,
and he instantly falls upon the ground. So while I am thinking over the
virtues of my friends, if the tea-kettle spurt out some hot water on my
stocking; the sudden pain breaks the weaker chain of ideas, and introduces
a new group of figures of its own. This circumstance is extended to some
unnatural trains of action, which have not been confirmed by long habit; as
the hiccough, or an ague-fit, which are frequently curable by surprise. A
young lady about eleven years old had for five days had a contraction of
one muscle in her fore arm, and another in her arm, which occurred four or
five times every minute; the muscles were seen to leap, but without bending
the arm. To counteract this new morbid habit, an issue was placed over the
convulsed muscle of her arm, and an adhesive plaster wrapped tight like a
bandage over the whole fore arm, by which the new motions were immediately
destroyed, but the means were continued some weeks to prevent a return.

9. If any circle of actions is dissevered, either by omission of some of
the links, as in sleep, or by insertion of other links, as in surprise, new
catenations take place in a greater or less degree. The last link of the
broken chain of actions becomes connected with the new motion which has
broken it, or with that which was nearest the link omitted; and these new
catenations proceed instead of the old ones. Hence the periodic returns of
ague-fits, and the chimeras of our dreams.