It may well astonish you, that you should have in your inside a taster who is not accountable to you; who experiences sensations of which you know nothing, and cannot even form an idea. Yet thus it is. The _pylorus_ actually tastes the paste which is in the stomach, and if it is not to his taste, that is to say, if the work of digestion has not sufficiently transformed it for use, he keeps the door relentlessly closed.

The porter up above has a thousand different tastes. He makes his bow to meringues, and admits wings of chickens. Fries, roasts, stews, things tender or crisp, sweet and salt, oily, greasy, or sour; amongall kinds he has friends whom he welcomes in succession; and it is well for us that he does so, for we share in all his pleasures.

The porter below, who works for himself alone, obscure and unknown down in his black hole, the porter below, I say, has but one taste, knows but one friend--a gray-looking paste, semi-liquid, with a very peculiar unsavoury smell, disagreeable enough to any one but himself, which is called the _chyme_, I scarcely know why, but it is what everything one eats turns into, without exception, be it delicate or coarse by nature. The great lord's truffle-stuffed pullet makes, as nearly as possible, the same _chyme_ as the charcoal-burner's black bread; and though the palate of the former may be better treated than that of the latter, the _pylori_ can enjoy but one and the selfsame sauce. Equality is soon restored in this case, therefore, as you see.

To be free to pass through then, the contents of the stomach must be reduced to the condition of _chyme,_ the only substance which finds favor with the _pylorus:_ and as, in the endless varieties of food which go to form our nutriment, some sorts turn into _chyme_ much more quickly than others, it follows, that by the aid of its discriminating tact (which is not easy to elude) the _pylorus_ allows some to pass, while it turns back others, until all in succession are converted into chyme. For example, in the case of a mouthful of bread and meat swallowed at once, the bread passes away on its travels long before the meat has done dancing attendance in the stomach, awaiting that transformation without which the _pylorus_ will never allow it to slip through.

This ought to make you seriously reflect on the danger of carelessly swallowing things, which, by their nature, are not susceptible of being converted into _chyme,_ particularly if they are too large to hide in the general paste, as a cherry-stone will sometimes do, so mixed up with other food as to pass unperceived by the _pylorus,_ over whose decisions we have no control, remember. It bangs the door to, be assured, in the very face of anything obnoxious without hesitation, and the poor stomach would find itself condemned to retain them for an indefinite period, unless by dint of prayers and supplications they should contrive to soften the stern guardian, who may at last get accustomed to their approach, and, perhaps, in a weak moment, allow them to pass as contraband goods; like a custom-house officer on a foreign frontier who will occasionally shut his eyes to a country friend's packet of tobacco. But the poor stomach has had to suffer a martyrdom meantime, while the dispute was pending, and before the intruder has been winked at by the porter.

I shall remember all my life the history of a peach-stone, which was related to me in 1831. I was at the time a youngster at the Stanislaus College, and (aided perhaps by the Revolution of July, which had recently occurred), it was just then discovered to be a proper thing to set about teaching the laws of nature to children. Consequently, for the first time in the history of schools, a professor of natural history was added to the instructors of Latin and Greek. I leave you to judge how we opened our ears to his lessons. When we arrived in the course of our new studies at the _pylorus,_ of which we had none