that their several cavities were evidently enlarged to a confiderable degree.

EXPER. XV.

Ivory not being found fufficient to refift the operation of digeftion, cylindrical tubes of tin were prepared, with a number of fmall holes in each of them. To a dog who had not got food for twelve hours, four of these tubes were given; in one was contained fixteen grains of roasted beef, in another as much veal, in a third the fame quantity of tallow, and in a fourth as much wheat-bread. The dog being killed at the end of ten hours, the beef and bread were found entirely diffolved; the veal had loft only ten grains, and the tallow eight grains of their original weight. The tubes were not in the least affected.

EXPER. XX.

Four of the cylindrical tin tubes were given to a sheep; the one contained fixteen grains of raw beef, another as much falmon, a third the fame quantity of turnip, and a fourth as much potatoes. On opening the ftomach, fix hours after the feveral tubes had been swallowed, the

fish and beef were not at all affected, whilft the turnip and potatoes were entirely diffolved.

The fame experiment was afterwards repeated, with this difference, that the feveral articles were all boiled; and the refult was exactly fimilar, the vegetables being entirely digested, while the animal fubftances remained unimpaired.

EXPER. XXIII.

A piece of roafted beef, weighing twelve grains, was put into a phial, with half an ounce of pure gaftric juice, taken from the ftomach of a dog that had fafted eighteen hours. Into another phial was put the fame quantity of beef, with half an ounce of water. Both phials were then placed in a furnace heated to about the 102d degree of Fahrenheit's thermometer. In the space of eight hours, the beef contained in the phial with the gastric juice of the dog, was entirely diffol ved, while that mixed with the water had not fuffered any change. At the end of twenty-four hours both phials were removed from the furnace that with the gastric juice emitted a rancid, pungent, though by no means a putrid fmell; while the other appeared perfectly putrid, and afforded a very ungrateful smell.

Although

Although the phial containing the beef and gaftric juice was very diligently attended to, yet no air bubbles, or any other fign of fermentation, was at all obferved.

These appear to be the most material experiments enumerated by Dr Stevens: And, from the refults of which he concludes, that digeftion is neither performed by the effects of heat, trituration, putrefcency, nor fermentation; but is folely effected by the liquor which is naturally fecreted from the coats of the ftomach. This liquor, our author obferves, is different in different animals, and is probably always adapted to the particular kind of food intended by nature for the nourishment of each diftinct fpecies of animals.

VI.

Differtatio Inauguralis Medica, exhibens Obfervationes Medico practicas et Chirurgicas. Auctore Joann. Frid. Wilhelm. Nev. Goettingae. 1776.

E are favoured by the author of these observations with a collection of cafes,

both

both medical and chirurgical, which, in the course of practice, had occurred to himself. Such of them as appear most remarkable shall be here related.

Haemoptyfis Peruviano Cortice fanata.

Mr Nev, we are told, was himself the subject of the first obfervation. Of an irritable conftitution and plethoric habit, and having been frequently liable to discharges of blood from the nofe, and to catarrhal disorders of the lungs, he was, at last, in the year 1771, feized with a spitting of blood. This fymptom first occurred when on horse-back, attended with a violent cough and fevere pain of the fide; and to thefe, fucceeded heat, thirst, head-ach, with other symptoms of fever. By the use of blood-letting, and cooling laxatives, the febrile fymptoms were, in due time, got the better of; but the spitting of blood still remaining, with a view to its removal, the Peruvian bark was at last resolved upon; and, by a continued use of this remedy, first in decoction, and afterwards in fubftance, the disorder was not only carried off for the time, but any return of it, which might otherwise have happened, effectually prevented.

A

A cafe, in many respects fimilar to the above, is afterwards related, in which the use of bark was likewise attended with the beft effects. A Woman aged 32 years, of an irritable habit of body, laboured at the fame time under a remittent fever, a spitting of blood, and profluvium menfium. Laxatives, nitrous, and other colling medicines having been prescribed with no advantage, the patient was, at last, put under the care of our author. The conftitution being by this time greatly impaired, by the continuance of the disorder, bark was immediately ordered, and with fuch fingular good effects, that, in the course of a few weeks, a perfect cure was obtained.

Febris intermittens tertiana, cum Amaurofi, Cortice Peruviano Janata.

An old man aged 75, of a plump robust habit, was feized, about the vernal equinox, with a remittent fever, which, together with the usual fymptoms of fuch diforders, was likewife attended with blindness. Emetics, laxatives, and chamomile bitters, were all prescribed, but with no advantage; the disorder, however, was entirely got the better of by the ufe of Peruvian bark, conjoined with valerian. Another inftance is related by

our