The question is really one of importance, when we have to apportion the rations of paupers, prisoners, soldiers, and sailors. Here we are forced to strike an average, although we know that on any average one man will necessarily have more, and another less, than is absolutely requisite; but the impossibility of arranging matters otherwise, unless food be so abundant that it may be left to the discretion of each to eat whatever amount he pleases, forces the adoption of some standard which experience rectifies on the whole. Dr. Pereira has furnished several dietaries adopted for masses of men, and from these the following is taken.

The scale of diet in the Royal Navy is thus given in the Regulations :

"There shall be allowed to every person the following quantities of provisions :—

"When fresh meat and vegetables are not issued, there shall be allowed in lieu thereof

Salt beef,
Flour,

lb.

lb.

}

alter-Salt pork, lb. nately Pease, pint.

“And weekly, whether fresh or salt meat be issued—

The daily allowance to the common soldier in Great Britain is 1 lb. of bread and 4 lb. of meat, making together 196 oz. of solid food weekly; for this he pays a fixed suin,

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namely, 6d. daily, whatever may be the market price. He furnishes himself with other provisions.

As to the quantity each man should eat when unrestricted, it is to be determined by himself alone We are notoriously apt to eat too much, and consequently waste much food, even when we do not injure ourselves. Our sensations are the surest guides, yet they do not always tell us with suffi cient distinctness when we have had enough: one thing is very clear, that to force the appetite-to continue eating after the stomach has once suggested" enough "—is sure to be injurious. Hospitable hosts, no less than anxious parents, should refrain from pressing food on a reluctant appetite; it is not kindness, although kindly meant.

In closing here our survey, we must confess that it has exhibited few reliable scientific data. Indeed, to some readers it may have seemed that our efforts have been mainly revolutionary, shaking foundations which promised security, and disturbing the equanimity of scientific speculation. It is a fact that Physiology is at present in too incomplete a condition to answer the chief questions raised respecting Food; and this fact it was desirable to bring into the clear light of evidence; for on all accounts it is infinitely better that we should understand our ignorance, than that we should continue believing in hypotheses which enlighten none of the obscurities gathering round the question. It is in vain that we impatiently turn our eyes away; the darkness never disappears merely because we cease to look at it.

7*

CHAPTER III.

DIGESTION AND INDIGESTION.

Happiness and misery connected with the Digestion-In what is science distinguished from ordinary knowledge?—The mechanical and chemical processes of Digestion the former only exists in the simplest animals-What takes place in the mouth-Chemical action of the saliva-Its mechanical action-" Bolting" the food-Mechanical action of the stomach-The gastric juice: its composition and origin-Pepsin and acid-Action of gastric juice on various substances-It arrests putrefaction-Lesson against over-eating-Influence of fats in digestion Influence of saliva in increasing the gastric juice-Quantity of gastric juice-Chymification equivalent to boiling-Why the gastric juico does not act upon the stomach itself-Intestinal Digestion-The bile: quantity and composition of; how affected by fats-What is meant by biliousness?-Tho part played by bile--It neutralises the action of gastric juice, and assists in the absorption of fat-The pancreatic juice acts on all substances-The intestinal juice completes Digestion-Nature of chyle-The various Causes of Indigestion.

'LET good Digestion wait on appetite." Much of our happiness depends on health, and health cannot continue without digestion. Riches, and honours, and the applause of crowds, are but poor compensations for the loss of that perpetual spring of pleasure which arises from the harmonious activity of all the functions; and the most prosperous of men must envy children and animals their prosperity of digestion. The misery of mankind, springing from many causes, is intensified by Indigestion, which lessens the fortitude to endure calamities, and increases the tendency to indulge in painfu! forebodings. Sorrow, come whence it may,

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is more lightly borne, and is briefer in its visitations, when the health is vigorous; and it cannot be vigorous without good Digestion. To those whose troubled secretions predispose them to gloom and fretfulness, small evils become magnified into calamities, and evils anticipated have the force of realities.

The marvels of Nature are an inexhaustible source of reverence to the reverential mind, and among these not the least marvellous is the admirable complexity of the apparatus on which Digestion depends. No sooner do we become acquainted with this complexity than our surprise is, not that many of us, imprudent and reckless as we are, should suffer from derangements of that function; but that any of us should continue to perform it with success seven days together. The more we contemplate this mechanism, the more wondrous its appears. The more we study the process, the more intricate its problems seem. Formerly the process was thought to be very simple; increase of knowledge brought increase of doubt; and now, whoever looks closely into the results of modern investigation will be surprised to find how little the enormous labours in all directions have added to our positive knowledge. The conquests of science have consisted in explaining certain details of the process, and in analysing the whole function of Digestion into sepa

rate acts.

And here we may pause to consider in what scientific explanation peculiarly consists, namely, in the discovery of those intermediate facts, not obvious, which link together the obvious phenomena. Thus it is a matter of vulgar observation that cattle eat grass, and that this grass returns, in the shape of manure, to effect the growth of fresh crops. The farmer, in knowing this, may be said to know as much as the philosopher; but the farmer only knows the facts which stand out, visible to all—the obvious arcs in the great

orbit of life; whereas the philosopher, not content with these, seeks to detect the hidden facts-the intermediate links of cause and effect, which constitute the chain. In proportion to his success in discovering these intermediate links, and in their order of succession, he approaches a scientific explanation of the vulgar observation. This scientific explanation has two great advantages: it ministers to the intellectual craving for knowledge, a craving which gives man his eminence; and it ministers to his practical aims, increasing his power over Nature by enabling him to foresee and to modify phenomena, and to adapt them to his uses. If he learns that silica* is an essential constituent of wheat, and that silica must be in the ground before it can enter the wheat, he learns two " intermediate facts" not at all obvious, which enabled him to adapt circumstances to his needs: if the earth be deficient in silica, he will add a fresh supply.

It is the same with Digestion. Every one knows that Food of various kinds is taken into the mouth, chewed, and swallowed; that it remains some time in the stomach, where it undergoes certain changes; that it then passes into the intestines, and separates into two portions, one of which nourishes the body, while the other is ejected as waste. These are the vulgar facts. But we cannot rest content with these. The intellect craves knowledge more precise, and practical wants require that the "intermediate facts" should be discovered.

THE FUNCTION OF DIGESTION.-The purpose of Digestion is to make Blood. To effect this there are many processes which, although closely connected with Digestion, are not really implied in it: such are Chewing the food, and Absorption. There are many animals which do not chew; there are many which have no absorbent vessels; yet all these digest. The function of Digestion is the function of the

Silica is the chief ingredient of flint, sandstone, and many earthy minerals.