blood, in
the veins of those animals, from the very heart of the extremity of the
limbs, is observable, by intervals, during the distresses of the dying
creature. Haller, Elem. Physiol. t. i. p. 216. Now, as the veins have
perhaps all of them a valve somewhere between their extremities and the
heart, here is ocular demonstration of the fluids in this diseased
condition of the animal, repassing through venous valves: and it is hence
highly probable, from the strictest analogy, that if the course of the
fluids, in the lymphatic vessels, could be subjected to microscopic
observation, they would also, in the diseased state of the animal, be seen
to repass the valves, and the mouths of those vessels, which had previously
absorbed them, or promoted their progression.

III. _Communication from the Alimentary Canal to the Bladder, by means of
the Absorbent Vessels._

Many medical philosophers, both ancient and modern, have suspected that
there was a nearer communication between the stomach and the urinary
bladder, than that of the circulation: they were led into this opinion from
the great expedition with which cold water, when drank to excess, passes
off by the bladder; and from the similarity of the urine, when produced in
this hasty manner, with the material that was drank.

The former of these circumstances happens perpetually to those who drink
abundance of cold water, when they are much heated by exercise, and to many
at the beginning of intoxication.

Of the latter, many instances are recorded by Etmuller, t. xi. p. 716.
where simple water, wine, and wine with sugar, and emulsions, were returned
by urine unchanged.

There are other experiments, that seem to demonstrate the existence of
another passage to the bladder, besides that through the kidneys. Thus Dr.
Kratzenstein put ligatures on the ureters of a dog, and then emptied the
bladder by a catheter; yet in a little time the dog drank greedily, and
made a quantity of water, (Disputat. Morbor. Halleri. t. iv. p. 63.) A
similar experiment is related in the Philosophical Transactions, with the
same event, (No. 65, 67, for the year 1670.)

Add to this, that in some morbid cases the urine has continued to pass,
after the suppuration or total destruction of the kidneys; of which many
instances are referred to in the Elem. Physiol. t. vii. p. 379. of Dr.
Haller.

From all which it must be concluded, that some fluids have passed from the
stomach or abdomen, without h