a mild and undefcribable delight, firft from the ftimulus of the aliment; and fecondly, from the diftenfion of this, and the increased action of other parts *.

If it should seem strange that pleasure arifes from the fimulus of food on the fentient nerves of this important organ, let us recollect only the effect of a moderate dose of opium to those unaccustomed to that stimulus. They are commonly fo tranfported with the pleafing fenfation it induces, that they feel, as they oftentimes exprefs themselves, as though they were in heaven, and enjoy fo perfect a pleasure, that no happiness in the world can furpass the charms of this agreeable ecstasy. On the other hand, what a terrible agony will two or three grains of crocus metallorum throw the whole fabric into; this part being of fo acute a feeling, that fome philofophers have for this reafon thought it to be the feat of the foul itself.

Befides this confideration, we muft here take notice,

South America; who, after fuffering months of hunger and fatigue, were reduced to fkin and bone. A table, fays BYRON, was fpread out for us by the Indians, with cold ham and fowls, which only we three fat down to, and in a fhort time we dispatched more than ten men with common appetites would have done, and yet we complained of being unfatisfied. For a long while we got up two or three times in the night to cram ourselves. Captain CHEAT ufed to declare, that he was quite ashamed of himself.

* Vide Law II,

that

that the ftomach, being diftended with food, preffes on the spleen*, and thereby occafions a greater quantity of blood to pass into the pancreas, and confequently a greater increase of the secretion from that vifcus ;-and by obstructing in some degree the paffage of blood in the descending trunk of the aorta, caufes an increased flux of blood to the head, and hence, after a full meal, inactivity and drowsiness †, and fometimes apoplexy ‡, enfue; and hence alfo proceed those flushings or rednefs in the face, fo confpicuous in weak and exhausted perfons.

The increased oxygenation of the blood from the fame circumftance has been before noticed, when on the fubject of ANIMAL HEAT, and the balance, that is conftantly found to take place, betwixt the hydrogen received in the stomach, and the oxygen air drawn into the blood

* The true office of the SPLEEW was the happy discovery of the ingenious Dr. HAIGHTON, Lecturer on Phyfiology to the Pupils of Guy's and St. Thomas's Hofpitals. It did not escape the penetrating mind of the Reverend Mr. TOWNSEND, and this coincidence of thought is a further proof of its truth. See the Guide to Health, page 33. Vide note †, page 215.

+ Mr. BRINDLEY, the famous canal engineer, mentioned to Dr. DARWIN that he had more than once feen the experiment of a man extending himfelf across the large ftone of a corn-mill, and that by gradually letting the ftone whirl, the man fell fast asleep. Dr. DARWIN.

See the Guide to Health.

Ff

while

while paffing through the lungs. Probably, from this cause it was, that more of Sir JOSEPH BANKS and Dr. SOLANDER's party did not perifh at Terra Del Fuego *. Hence the importance of the confideration of food † in all inflammatory states of the body. And hence the confideration of a peculiar diet for the removal of many dif orders incident to the human frame.

We will now attempt to trace the food in its digefted form, after it is thrown out from the ftomach into the inteftines.

The aliment having remained during two or more hours in the ftomach is converted, firft, into a greyish

* They had with them a bottle of rum, and a failor, who was feized as bad as the black, recovered from his torpor by drinking of the rum. Vide Cook's Voyages. See alfo the Section on Animal Heat, page 81.

Mr. SUTTON, in the vicinity of Plymouth, inoculated a lady, who on the third day after the commencement of the irruptive fever, had five or fix red pimples, which formed gradually into puftules.

During the progrefs of the disease, as fhe fat at table, fhe expreffed uneafinefs, and wifhed to have stronger evidence, than yet appeared, that she had the fmall-pox. Mr. Sutton told her, that she had only to eat a portion of hare, which was on the table, and drink one glass of wine, and fhe would have fufficient evidence to fatisfy her mind.

She accepted the propofal; the fever increased; and the small-pox, from being difcrete, became confluent.

Mr. Sutton then took fright, and delivered her to the care of Drs. Mudge and Huxham, by whofe watchful attention fhe was carried fafely through the fecondary fever. Vide the Guide to Health, page 156.

pulp,

pulp, which is ufually called chyme. This chyme, or fluid, paffes out of the pylorus, or right orifice of the ftomach, the fibres of which relax to afford it a paffage ; while the groffer and lefs altered particles remain in the living retort, to adopt the expreffion of the Reverend Mr. TOWNSEND, till they acquire a fufficient fluidity to pass into the intestinal canal. As the digefted food enters the duodenum, it ftimulates the common duct of the gall bladder and the liver, and from a law in the animal economy, which has given the highest fenfibility to the nerves at the mouths of the feveral ducts, which, by a sympathetic communication, occafions their feveral glands either to fecrete or pour out a greater quantity of fluid, the chyme receives a full supply of bile, and of faliva, fecreted from the pancreas † ; it also intermingles with mucus from innumerable exhalent arteries, which still farther anamalizes the chyme.

The commencement of the intestines.

The pancreas is a large gland, which lies near the ftomach, and difcharges, by a short duct, into the intestines, a liquor, which it separates from the blood. It is difficult to collect any quantity of this juice, because it is n-t lodged in any particular receptacle, but flows from the gland into the intestines, near the upper orifice of the ftomach. However, in dogs this has been executed by tying a bottle near the duct of the gland, while the animal was living, by which a quantity of the juice has been collected, and found in appearance to refemble the fuliva.

Ff2

The

The inteftinal canal is five or fix times as long as the body, and forms many circumvolutions in the cavity of the abdomen, which it traverfes from right to left, and again from left to right. The inner coat of the intestines, by being more capacious than their exterior tunics, occafions a multitude of plaits *, at certain regular diftances from each other, and thefe become lefs and lefs, and at farther intervals, as they defcend. This difpofition will be found to afford a ftill farther proof of that divine wisdom, which the anatomist and physiologist cannot fail to observe in all their purfuits; for if the intestinal canal was much fhorter than it is; and if its inner furface was smooth and deftitute of plaits; the aliment would confequently pafs with great rapidity to its termination, and fufficient time would be wanting to affimilate the chyme, and for the necessary absorption of it by the numerous villi, or hair-like projections †, which terminate in lacteals: fo that the body, unless constantly replenished, would be deprived of the supply of nutrition, which is fo effential to life and health :but the length and circumvolutions of the inteftines, the inequality of their internal surface, and the course of the

* Called by anatomifts valvula conniventes.

+ Vide the Section on Animal Heat, and note

I

page 87.

aliment