tillatione faucium._ If the throat be slightly tickled with
a feather, a nausea is produced, that is, an inverted action of the mouths
of the lymphatics of the fauces, and by direct sympathy an inverted action
of the stomach ensues. As these parts have frequently been stimulated at
the same time into pleasurable action by the deglutition of our daily
aliment, their actions become strongly associated. And as all the food, we
swallow, is either moist originally, or mixed with our moist saliva in the
mouth; a feather, which is originally dry, and which in some measure repels
the moist saliva, is disagreeable to the touch of the fauces; at the same
time this nausea and vomiting cannot be caused by the disagreeable
sensation simply, as then they ought to have been increased exertions, and
not decreased ones, as shewn in Section XXXV. 1. 3. But the mouths of the
lymphatics of the fauces are stimulated by the dry feather into too great
action for a time, and become retrograde afterwards by the debility
consequent to too great previous stimulus.

7. _Vomitio cute sympathetica._ Vomiting is successfully stopped by the
application of a blister on the back in some fevers, where the extremities
are cold, and the skin pale. It was stopped by Sydenham by producing a
sweat on the skin by covering the head with the bed-clothes. See Class IV.
1. 1. 3. and Suppl. I. 11. 6.

* * * * *

ORDO III.

_Retrograde Associate Motions._

GENUS III.

_Catenated with Voluntary Motions._

SPECIES.

1. _Ruminatio._ In the rumination of horned cattle the food is brought up
from the first stomach by the retrograde motions of the stomach and
oesophagus, which are catenated with the voluntary motions of the abdominal
muscles.

2. _Vomitio voluntaria._ Voluntary vomiting. Some human subjects have been
said to have obtained this power of voluntary action over the retrograde
motions of the stomach and oesophagus, and thus to have been able to empty
their stomach at pleasure. See Sect. XXV. 6. This voluntary act of emptying
the stomach is possessed by some birds, as the pigeon; who has an organ for
secreting milk in its stomach, as Mr. Hunter observed; and softens the food
for its young by previously swallowing it; and afterwards putting its bill
into theirs returns it into their mouths. See Sect. XXXIX. 4. 8. The
pelicans use a stomach, or throat bag, for the purpose of bringing the
fish, which they catch in the sea