Salt in it, clogs, and prevents the fudden Hurry of the Steam, prevents Surfeits, Vomitings, &c. occafioned by too great an Irruption of Juices, and composes the Agents, and does juft the Reverse of what is attributed to it, does not help, but hinder the Agents in Digeftion. Cheese, that has Abundance of Salts in it, has the fame Effect as Cheese, but the Salts in it have the quite contrary Effect, for all forts of the fharp Salts forward Digeftion: but chiefly Sea Salt, which is mixed with the Cheese, and that either joined or feparate, prevents fudden Hurries of the volatile Salts, of which more hereafter. 'Tis pretty evident that AlteChanges of ration of Diet, will in Time make the should be. Juices of the Stomach blunter or sharper, made gra-and the Steam ftronger or weaker. Al dually, and terations either Way, fhould be made

Of

Diet. It

why.

very flowly; for that which is hard to digeft, will not be digefted by few or blunt Juices, and that which is eafy to digeft, will be too much digefted, or made too fharp, by too many, or too fharp Juices; and that which is thrown out by a strong Steam, will be too heavy to be circulated by a weak Steam; and that which is thrown out by a weak Steam, will be hurried too faft by a strong one. Whe

ther

ther there be not frequent Errors in prefcribed Diets, efpecially on the weak Side, deferves to be confidered.

CHA P. XV.

Some Thoughts about the Caufes of Sleep; and what is done during Sleep:

The

rally in

IN Order to know what occafions an Inclination to Sleep, and what is performed in Sleep, 'tis neceffary to confider the Circumftances we are in when we feel that Inclination; when we have flept a while, and when we have no farther Inclination. One has almost con- Times ftantly an Inclination to fleep, as foon as when one one has eaten and drunk too much, for is genethen the Juices, Corpufcles of Heat, Salts, clined to &c. will for a little Time be entangled, Sleep. and sheathed in the Meat, or be divided and overpowered, fo that little Steam will go off, and one becomes dull, heavy, &c. When there is a great Quantity of cold Phlegm lodged in one's Stomach, Guts, &c. which hinders the Agents from fending out fufficient Steam, to circulate the Blood, &c. When long, or violent, Action has wafted the Steam, and left not fufficient to circulate the Blood, exVOL. X.

N

tend

tend the Parts, &c. When one has fat, or laid ftill a good while, without Action Animal of Body or Mind, fo that the FermentaProcess. tion is not affifted by Motion or Action,

and the Steam moves weakly: When one has been inactive a good while in a hot Place, that the Pores are open, and the Steam perfpires too much, or too much of the finer, thinner Steam: When one has fat long in a crowd of People in a clofe Place,, fo that the Air which goes into the Lungs is full of Heat and Steam, does not discharge a due Share of the Steam out of the Lungs, especially of the Heat, and that opens the outward Pores, and perfpires too much there.

Some

People have a great Inclination to fleep when they are almost drunk, whether the Liquor overfets the Ferment in their Stomachs, or the Steam is emitted fafter than it can be discharged, and hinders Circulation, &c, or more, or craffer is fent into the Head, than is neceffary for the Nerves, I cannot determine. We need moft Sleep in cloudy, foggy Weather, and fome Creatures fleep all the Winter, till the Heat raife Steam in them to thin their Blood, &c. We ought also to confider all the Contraries which prevent Sleepiness, as eating and drinking fparingly, a clear Stomach,

C

ders that

Stomach, and a brifk Ferment, a moderate Quantity of fpirituous Liquor, moderate Action, or any other Cause which moves or excites a fufficient Steam from the Stomach or Guts to circulate the What hin Blood, or which fhuts the Pores when Inclinathey are too much opened by Heat with- tion. out, or Action, fo that the Steam perfpires as faft as it rifes, and prevents its farther Waste, and keeps in the fucceeding Steam, to restore our Strength and Vigour, as cool Air, a ftrong Preffure of the Atmosphere, &c. Whether the Air has the fame Effects upon the Pores, or Bladders in the Lungs, as it has upon those in the outward Skin, whether cool Air condense the Steam there, and straighten the Pores, or whether it bear off more Steam than hot Air does, I am not certain. One cannot fleep, or Sleep does folutely one little good unless one be kept mode-prevents rately warm, and unless there be fome-Sleep. thing in the Stomach or Guts lately digefted, to prevent any Uneafiness by the Cold without, or by the gnawing of the Juices within. When the Steam goes off too fharp, or too little entangled, or with too fmall Burthens, and frets or heats the Parts too much, or when too much of it goes and hurries the Blood too faft, it N 2

puts

What ab

puts one into a Fever, and hinders one from fleeping; and when one fleeps, either the Fever abates by Sleep, or the Fever is begun to abate before one fleeps; so it feems that too little Steam, or grofs inactive Steam, caufes Sleep; and too much or too ftrong, or too active Steam hinders us from fleeping. When one fleeps, the Juices have Time to fecrete into the Stomach, the Agents have more Time to act, or repeat their Actions, in the Stomach and Guts, because there is no Action to force off the Steam, and a little ferves to circulate the Blood, because it moves very flowly, because the Lungs move, and refpire very flowly, and becaufe the little Steam, which perfpires at the Pores by being defended from the Motion of the Air, is not condensed, or dispersed, but rebounds and keeps the Body warm, and the Fluids thin; and 'tis very likely, that in the regular flow Motion of the Blood during Sleep, the Corpufcles adhere, to fupply those born away from the Parts in Action, and that several Secretions may be made to fupply the Veffels, and especially the Nerves, with each their proper Juices, Steam, &c. for the feveral Uses to which they are employed. When every Thing is in fresh Motion,

the