of chamomile, and the vitriol of zinc: for,
according to the fourth law of irritation, the stomach will not long be
obedient to a stimulus so much greater than is natural; but its action
becomes first tremulous and then retrograde.

7. When the motions of any vessels become retrograde, less heat of the body
is produced; for in paroxysms of vomiting, of hysteric affections, of
diabetes, of asthma, the extremities of the body are cold: hence we may
conclude, that these symptoms arise from the debility of the parts in
action; for an increase of muscular action is always attended with increase
of heat.

8. But as animal debility is owing to defect of stimulus, or to defect of
irritability, as shewn above, the method of cure is easily deduced: when
the vascular muscles are not excited into their due action by the natural
stimuli, we should exhibit those medicines, which possess a still greater
degree of stimulus; amongst these are the foetids, the volatiles,
aromatics, bitters, metallic salts, opiates, wine, which indeed should be
given in small doses, and frequently repeated. To these should be added
constant, but moderate exercise, cheerfulness of mind, and change of
country to a warmer climate; and perhaps occasionally the external stimulus
of blisters.

It is also frequently useful to diminish the quantity of natural stimulus
for a short time, by which afterwards the irritability of the system
becomes increased; according to the third law of irritation
above-mentioned, hence the use of baths somewhat colder than animal heat,
and of equitation in the open air.

_The catalogue of diseases owing to the retrograde motions of lymphatics is
here omitted, as it will appear in the second volume of this work. The
following is the conclusion to this thesis of_ Mr. CHARLES DARWIN.

Thus have I endeavoured in a concise manner to explain the numerous
diseases, which deduce their origin from the inverted motions of the hollow
muscles of our bodies: and it is probable, that Saint Vitus's dance, and
the stammering of speech, originate from a similar, inverted order of the
associated motions of some of the solid muscles; which, as it is foreign to
my present purpose, I shall not here discuss.

I beg, illustrious professors, and ingenious fellow-students, that you will
recollect how difficult a talk I have attempted, to evince the retrograde
motions of the lymphatic vessels, when the vessels themselves for so many
ages escaped the e