HUMAN PHYSIOLOGY.-V. DESTRUCTION of tissue and change of structure are the necessary consequences of even those functions that are indispensable to the continuance of life. Every breath we draw, every beat of our hearts, causes waste of the material of the body; and this waste is largely increased when, in addition to these passive and involuntary actions, we add active exertion. We cannot lift a finger or walk a yard without helping forward this change, which is for ever proceeding.

Now, as waste and decay take place thus continually, it follows that if the body is to be sustained-if provision is to be made for its growth and increase-new material must be as constantly furnished as the old tissues waste. It is to provide this new material to supply the place of the destroyed structures that we take food. In considering the subject of food, we shall have to look at it in two lights-first, as to its objects; secondly, as to the sources whence it is derived. It has been already said that the object of food is to sustain and nourish the body, to enable it to perform the work it has to do, and in youth to increase its size and grow to its full proportion. For the proper performance of these duties two great differing classes of nourishment are necessary-one called the plastic, or nitrogenous, the elements included in which are supposed to go directly to the formation of the tissues; all of the members of this class contain, as its name implies, a certain proportion of nitrogen, and are derived mainly, though not entirely, from the animal kingdom; the chief of these are fibrine, albumen, caseine, gelatine, and gluten. The first four are almost exclusively of animal origin, whilst the gluten is a vegetable product; fibrine, albumen, and gelatine enter into the composition of butchers' meat, poultry, and fish; caseine is found in milk; gluten in most vegetable foods, in the largest proportion in wheat. The other class of food is called carbonaceous, or heat-producers; this supplies the fuel for the respiratory process, and furnishes the heat of the body. The elements included in this class come from both the animal and vegetable, and include the fats, starches, and saccharine principles. The office of all these, as has been said, is to produce heat, and for this purpose the fats are the most powerful agents; but, in addition to this their main office, they serve other important purposes in aiding in the digestion of the nitrogenous elements of the food. The digestive power of the pancreatic fluid depends in a great measure upon the presence of fat, and it is believed that it is largely concerned in the production of bile. Its presence in large quantities in the nerve-centres shows that it serves some important office in nervous action, and by its mechanical presence it gives roundness and suppleness to the form, and, owing to its bad conducting power, helps to preserve the heat of the body. The starches and sugars are also heat-producers, but by no means such energetic ones as the fats; these, by their digestion, become changed into various acids. They are largely concerned in the production of fat, as is shown by the rapidity with which animals fatten that are fed on diets rich in farina and sugar.

As to the sources of food, they are confined entirely to the animal and vegetable kingdoms. No instance has yet been net with where an animal had the power of deriving its nourishment directly from the mineral world; although it is a curious fact, that in some of the deep sea-dredgings recently made, when the mud from the bottom of the ocean was examined, it was found to teem with abundance of the lowest forms of animal life, but did not present a trace of any vegetable organism. Man almost universally derives his food from both the animal and vegetable kingdoms; and there can be little doubt, from the formation of his teeth and the structure and shortness, as compared with vegetable feeders, of his alimentary canal, that he was intended so to do; for, although it cannot be denied that it is possible for him to derive all the elements necessary for his support from the vegetable world alone, it is quite certain that, to enable him to do so, he must expend a much larger amount of vital force than is called for when he lives on a mixed diet; he does, in fact, in the latter case, utilise the work already done by the lower animal on which he feeds, as that in its turn has appropriated and made its own the work the vegetable has accomplished, in absorbing and preparing the mineral elements which, without this preparation, would have been unavailable for the support of animal life.

TOL. V.

Such, then, being the objects and the sources of the food of man, we must now consider in detail the different varieties of which this food is composed. But, before doing so, it may be well to stop and consider for a minute the quantity of the primary elements that are absolutely necessary for the support of life. By a careful calculation it has been found that a man requires, to keep himself alive, a daily supply of 4,100 grains of carbon and 100 grains of nitrogen. These quantities are contained in two pounds four ounces of bread; but though this or even a larger quantity of bread or of any other article containing an equal amount of carbon and nitrogen would sustain life for a short time, it has been found that health cannot be maintained on any one article of diet save milk, though it contain within itself all the necessary elements for the support of life. Dogs fed on white bread and water died of starvation in fifty days; rabbits and guinea-pigs fed exclusively on any of the following substances-wheat, oats, barley, cabbage, or carrots-died in fifteen days, whilst if they were given in succession or alternately, no evil results followed. The first great necessity for the support of animal life is water, for without it the others would be useless. The importance of water will be at once perceived when we remember that 75 per cent. of the blood and of the fleshy covering of the body is composed of it, and that from the body in the course of the day about five pounds and a half of water is excreted by the lungs, the skin, and the kidneys. It is taken into the body, both separately and in combination with other foods, there being, in fact, no food, however solid, which does not contain a certain proportion of it, and of many it forms the largest part. Many succulent vegetables contain 80 to 90 per cent.-potatoes, 75 per cent.; new milk, 88 per cent.; and beer, ale, skim milk, etc., 90 per cent. The duties water has to perform in the body are mainly two: it serves to dissolve the food, and enable the nutritive parts of it to be carried into the circulation; and on the other hand, it dissolves out the worn materials and conveys them out of the body. In addition to these functions, by its evaporation from the surface of the body and the air-passages. it helps to regulate its temperature. Of the foods derived from the animal kingdom, we must first consider milk. This may be taken as the type of what every food should be, for it contains within itself all the elements necessary for the support of the animal organism. In some countries it forms the chief diet of the people, and wherever it can be easily procured it is largely consumed. Its component parts are water; caseine, which represents the albuminous group; cream or butter, representing the fats and sugar of milk, the saccharine, the latter two being the carbonaceous elements. The proportion of these constituents varies according to the animal from which it is derived. Asses' milk is that which most nearly approaches in composition the human milk, but this has less than a third of the quantity of the fatty element; whilst cows' milk, containing nearly the same proportion of cream, has three times as much caseine, and only two-thirds as much sugar of milk. To make cow's milk, therefore, a fit food for young infants, it is necessary that it should be diluted with water, and have sugar of milk added to it. Cheese, which is the caseine of milk separated from it by the addition of an acid, contains a large proportion of nitrogen, and is a very nutritious, but not very digestible substance

Our supplies of meat food are derived from several sources, but mainly from the ox, sheep, and pig; its nutritive value depends principally upon the proportion of lean which it contains, but there is little difference in the relative nutrition of the meats derived from these three sources. Horseflesh is but little used in this country, but has within the last few years come into rather extensive demand in France. Venison, and the flesh of other wild animals, is equally nutritious with beef and mutton, and when properly cooked is more digestible. Poultry and rabbits are not in themselves very nourishing, as they contain too little fat. Fish also, with the exception of mackerel, eels, and salmon, are deficient in fat, and in nutritive value very inferior to flesh. Eggs contain a certain proportion of fatty matter, but a much larger proportion of nitrogen; the fatty matter is found in the yolk, but it is preferable to take the whole egg than an equal weight of the yolk alone. Fats in some form are an absolute necessity as an article of food. Those derived from the animal kingdom are mainly butter, lard, suet, and dripping; in most cases it exists in sufficient quantity in

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the other articles of food. From the vegetable kingdom are derived various oils and fatty matters, such as olive oil, cocoa butter, etc.

Of vegetables the cereals occupy the principal place; the chief among them in this country is wheat; from wheat is prepared the flour of which the bread that is eaten by the great bulk of the people of the British Islands is made. The grain of wheat is formed of an outer covering of bran, inside which there is a layer of nitrogenous matter, and within that the flour. The latter should constitute 80 per cent. of the whole grain when ground. The meal is passed through a series of sieves, which reduce it to the varying degrees of fineness known as "households" and "best flour;" practically, households is the best for family use, for though in casting away the bran a certain proportion of the nutritive, and a large amount of the mineral elements of the wheat are lost, yet 50 per cent. of the bran is completely indigestible, and when taken into the alimentary canal, instead of adding to the nutritive property of the food, acts as an irritant, and thus causes waste, and probably prevents the absorption of even some of the other nutritive elements. The other grains used in this country as food are mainly oats, barley, Indian corn, and rice. Oatmeal, which is so largely used in Scotland, is made by grinding the whole grain, deprived of its outer husk, into a rather coarse powder; it is more nutritious than wheaten flour, but not so easy of digestion, and cannot be made into bread, but is used in the shape of cakes or porridge: it is still very largely consumed in Scotland and by the labouring classes of England. The grain, deprived of its outer skin and crushed, is called groats, and is much used for the preparation of gruel.

The use of barley meal prevails extensively in the north of Europe, but not so much in England as formerly; yet even now a good deal is consumed in the southern counties and in Wales. The flour resembles that of wheat very much in appearance, but is not so nutritious, and, like that of the oat, will not by itself make good bread; it is generally eaten in the shape of cakes, or as porridge. Barley, when deprived of its husk and rounded, is called "pearl or Scotch barley," and is much used for making drinks for invalids, and for thickening soups.

Maize, or Indian corn, since the famine in Ireland, has been extensively used in that country, and it forms the largest part of the farinaceous food of the inhabitants of America, Italy, and Spain. The meal is very nutritious, but has a peculiar harsh taste, and does not make good bread. It is generally eaten in the shape of stirabout, or porridge, with milk or treacle. By its exclusive or very large use the health of the people fed on it is found sooner or later to suffer; diarrhoea is often set up, and in Italy it is said to produce a peculiar disease of the skin-a kind of leprosy, accompanied by great depression and melancholy, with a tendency to commit suicide by drowning. In America the young green ears are eaten boiled in milk, and form a very agreeable dish. The meal ground finely, and deprived of its acrid principle by a chemical process, forms the numerous corn flours so much in favour now for the pre

paration of puddings, etc. Rice is the food of the natives of India and China, but in this country is used more as an article of luxury than as a necessary food. In nutritive power it is less than the other cereals, but much exceeds them in the proportion of its carbonaceous or heat-forming element; it is, therefore, a good adjunct to those meats which contain much nitrogen, such as poultry, veal, and fish. In times of scarcity it has been used as a substitute for potatoes, but cannot permanently supply their place, either on the score of nutriment or economy.

There are several other varieties of grain used in various parts of the world, but in this country they are almost entirely unknown.

The next great class of vegetable foods is that of the legumes; this includes peas, beans, lentils, and various other less used pulses. Of these, peas are the most generally and largely consumed, and may be taken as a type of the class; they are the most nutritious of all the vegetable foods, being rich in nitrogen, and also somewhat exceeding wheat-flour in the quantity of carbon they contain; they should never be used whole or with their skins, as these are completely indigestible, and, like the bran of wheat, cause irritation and consequent waste of the other parts of the food.

We come now to another great division of vegetable foods

the starches. This includes arrowroot in its various varieties, sago, tapioca, tous les mois, etc.; all these consist almost entirely of starch, are very poor in nitrogen, and rich in carbon, consequently have very little nutritive value, but form useful foods when cooked in milk, especially for invalids; if water only is used in preparing them, they form a jelly-like mass, which is only very partially digested. Of that class of food which goes by the common name of vegetables the potato stands first, both on account of its more extensive use, and its economy and nutritive power as compared with the other va rieties. "Its flavour is agreeable and constant, its supply abundant, and its preparation easy; its action in the body is unaccompanied by any inconvenience, and, in reference to the country population, its cost is small." Of its history, it is well known that it was introduced into this country from America by Sir Walter Raleigh in the sixteenth century, and has ever since that time been steadily advancing in popular favour; so that now it is in this country more extensively used than any other food, save, perhaps, wheaten bread. Its absolute nutritive value is not great, and it consequently requires to be eaten with some nitrogenous adjunct, as buttermilk in Ireland. The mealy varieties are the most digestible, and boiling in the skins is the most economical method of cooking them.

Green vegetables and the other roots may be classed together. Of these, the parsnip stands next to the potato in point of nutriment, then carrots, then turnips and onions. All these vegetables are more valuable on account of their anti-scorbutic properties than simply for their nutritive qualities. In this respect the potato still holds the first rank, and, in consequence of this, it is now an almost universal practice to provide potatoes, either fresh or preserved, as part of the dietary of seamen and passengers on board ship.

Other materials for food are occasionally found amongst the sea-weeds which so profusely strew our shores, and amongst the multitudinous varieties of fungi. Of the latter, the only ones of any importance, or in general use, are the common mushroom and the truffle, and these must be looked upon rather as flavourers or condiments than as food.

Very widely distributed and in extensive use is the next class of food-the sugars. These, like the starches, are deficient in nitrogen, are heat-producers and not tissue-formers, save as regards fat. Sugar is met with in two forms-solid as sugar, and liquid as molasses; that which is used in this country is prepared almost exclusively from the sugar-cane; but a very large quantity, used mostly in France, is extracted from the beet-root; and in America a considerable part of the supply is derived from the maple tree.

Other items derived from the vegetable kingdom are condiments and spices. These, whilst having no nutritive value of their own, act as flavourers; and thus food which, without them, would be insipid and repugnant, by their aid is rendered pleasant and palatable.

Two more classes remain, both beverages, and, in some respects, antagonistic ones. The first includes tea, coffee, and cocoa; the second alcoholic drinks.

Of the first it may be said that their use, or that of substitutes similar in kind, is spread over the whole world. The main elements necessary seem to be "an astringent matter, a volatile oil, and a crystallisable body rich in nitrogen." Vegetable infusions containing these principles are used equally in the arctic region as in the tropics. As to the part they fulfil in the animal economy, but little is satisfactorily settled. That they have little direct nutritive power is clear from their composition.

Dr. Edward Smith states that tea promotes the vital funetions of the body, and assists in the transformation of fatty and starchy foods, in this way quickening digestion; that it increases the action of the skin and induces perspiration, so lowering the temperature of the body; that it increases the respiratory function, and so causes an increase in the quantity of carbonic acid expired by the lungs. He also alludes to the lightness and cheerfulness which follow its use, and have earned for it the title of "the cup that cheers but not inebriates.” On the other hand, to excessive tea-drinking many physicians attribute a large quantity of the dyspepsia so common at the present day. Coffee is said to have in some respects a contrary effect to that of tea (acting like alcohol), in that it lessens the action of the skin, and does not affect the respiratory function to the same degree as tea.

Cocoa, in addition to the other principles common to it and tea and coffee, contains 56 per cent. of solid fat, called cocoa butter, and is consequently much more nutritious than either of the others; but this large quantity of fat is rather an objection to persons with weak stomachs, and to obviate this many excellent preparations of cocoa are now made, in which a certain proportion of the fatty matter is removed.

The use of fermented liquors in some shape is even more ancient and widely spread than that of the previous class. Those in use in this country may be divided under three heads -malt liquors, wines, and ardent spirits. The first class contains the largest amount of nutriment, wines the next, and spirits hardly a trace. But their value as articles of food does not depend on the amount of nutriment they contain. They all act as stimulants to the nervous system, and increase the respiratory changes, but their action varies according to the kind of alcohol taken. Beer and ale act on the respiratory functions in consequence of their saccharine and nitrogenous elements; wine, cider, and perry have similar actions; brandy and gin lessen the respiratory function; whisky is uncertain; and rum, like ale, is a true restorative, and sustains the vital powers. Their mode of action and their ultimate destination is still a matter of dispute. Liebig thinks they are burnt or oxidised in the body, and thus go to produce heat. Dr. E. Smith and others believe that they are simply nerve-exciters, and pass unchanged out of the system. Dr. Thudicum holds that they are oxidised in the body, and are a true food.

The only other elements to be mentioned are the mineral elements. These are mainly phosphorus, sulphur, potash, soda, iron, and magnesia. All of these are taken in combination with the other elements of food, but there is one other which requires to be taken in larger quantity than it can be met with in combination. This is salt. The absolute necessity of a certain portion of this element is proved by the fact that animals fed on food from which all salt has been removed die rapidly of starvation. Its presence also in large quantities in all the secretions is another evidence of the same necessity. So well has this been understood in all time, that one of the most severe punishments of barbarous ages was to feed criminals on food destitute of salt. The office it fulfils is uncertain, but it is highly probable that it chemically changes the food into a condition enabling it to be absorbed.

We have now considered all the main factors of the food of man, and in the next paper shall describe the changes that food undergoes in the alimentary canal, and trace it to its final desti

nation-the blood.

READINGS IN LATIN.-XI.

PLAUTUS.

LATIN comedies are among the earliest specimens of Roman authorship that have come down to our time; and of the many authors who have distinguished themselves by their productions in this branch of literature, Plautus and Terence are the only two with whose works we are at all intimately acquainted. The forms of their works are based upon Greek originals, as is the case with nearly all Roman poetry, the scenery being laid in Greece, and the very names of the characters being Greek also. Indeed, many of these plays are acknowledged adaptations of existing Greek comedies, while, strangely enough, the sentiments expressed are those of inhabi. tants of Rome. But although, as we have said, these comedies date from an early period in the history of Roman literature, the dramatic art was not of remarkably early growth in Rome. Four centuries had elapsed from the building of the city before dramatic exhibitions were introduced there for the first time, and the comedies of Plautus bear a date not very long posterior to that period. Plays were first introduced into Rome from Etruria, which was in all probability colonised from Greece at a very early period, and thus the dramatic art itself may be said to have come to Rome indirectly from Greece. Considering the early dates of the comedies of Plautus, they are in every respect very remarkable productions; the plots are carefully and intelligently elaborated; the language, though archaic in form and construction, is plain and intelligible, and the humour genuine and seldom offensive. Indeed, one can hardly understand how Horace, a man of refined taste, and evidently very capable of appreciating humour, could pass upon

the writings of Plautus tho severe criticism in his "Ars Poetica," lines 270-272 —

"At vestri proavi Plautinos et numeros et
Laudavere sales; nimium patienter utrumque,

Ne dicam stulte, mirati."

(But your ancestors praised the poetry and wit of Plautus, according him in both respects a lenient, not to say stupid admiration.)

M. Accius Plautus, or T. Maccius. Plautus-for there is some dispute about the correct form of his name, was born B.C. 254, and died B.C. 104. He lived, accordingly, about the period of the Second Punic War.

Our specimen of Plautus is taken from his comedy of the "Trinummus," or Three Pieces of Money, adapted, as the author says in the prologue, from a Greek original-"Philemo scripsit, Plautus vortit barbare" (Written by Philemo, turned by Plautus into the vernacular). The plot turns upon a sum of money which has been entrusted to one Callicles by Charmides for the benefit of his son during his absence in foreign lands. In the eyes of his friend, Megaronides appears to have betrayed his trust, and he accordingly calls upon him to explain his conduct. He is able to do so satisfactorily, and reproaches himself for his ill-grounded suspicions.

TRINUMMUS, ACT I., Sc. 2, 1. 150-185.
MEGARONIDES-CALLICLES.

ME. Pausa. Vicisti castigatorem tuum;
Occlusti linguam; nihil est, qui respondeam.
CA. Nunc ego te quæso, ut me opera et consilio juves,
Communicesque hanc mecum meam provinciam.
ME. Polliceor operam.
CA. Ergo ubi eris paullo post?
ME. Domi.

CA. Num quid, priusquam abeo, me rogaturu's? ME. Vale.
Nihil est profecto stultius, neque stolidius,
Neque mendaciloquius, neque argutum magis,
Neque confidentiloquius, neque periurius,
Quam urbani assidui cives, quos scurras vocant.
Atque egomet me adeo cum illis una ibidem traho,
Qui illorum verbis falsis acceptor fui:

Qui omnia se simulant scire, nec quidquam sciunt.
Quod quisque in animo habet aut habiturust, sciunt:
Sciunt id quod in aurem rex reginæ dixerit ;
Sciunt, quod Juno fabulata est cum Jove;
Quæ neque futura neque facta, illi sciunt tamen.
Falson' an vero laudent, culpert, quem velint,
Non flocci faciunt; dum illud, quod lubeat, sciant.
Omnes mortales nunc hunc aibant Calliclem
Indignum civitate ac sese vivere,

Bonis qui hunc adulescentem evortisset suis.
Ego de eorum verbis famigeratorum inscius
Prosilui amicum castigatum innoxium.
Quod si exquiratur usque ab stirpe auctoritas,
Famigeratori res sit cum damno et malo.
Unde quidque auditum dicant, nisi id appareat,
Pauci sint faxim, qui sciant, quod nesciunt,
Hoc ita si fiat, publico fiat bono.
Occlusioremque habeant stultiloquentiam.

NOTES.

150

155

160

165

170

175

180

185

150. Pausa appears to be the imperative of an old verb, pausare, to cease; from the Greek Taveir. In some old writers the word pausa is found as a substantive, equivalent to quies. Castigatorem, your accuser; meaning himself.

151. Occlusti-contracted for occlusisti. 153. Communicesque, etc., and undertake to share this charge of mine with me; viz., the guardianship of the treasure on behalf of the son of Charmides. thing for the welfare of which you have to provide. Provinciam, from providentia (pro-video), means any

154. Ergo is used here without the illative force (therefore) which usually bears, and simply serves as a link in the conversation, "Well, where will you be in a short time from this?” Post for post hac.

155. Numquid vis? An ordinary formula of leave-taking among the Romans, meaning literally, "Do you wish anything of me?" "Can I do anything for you?"-Cures tuam fidem, preserve your character, i.e., don't undeceive for the present the people who believe you are acting basely. Fidem may be used in a bad as well as a good sense.-Fit sedulo, kt., it is being done with care; translate, I'll take 156. Sed quid ais? An expression used in colloquial Latin when the speaker wishes to call special attention to some fresh subject he is about to introduce; lit., but what have you to say on this point; translate, But look here.-Ubi-habet, where does he dwell? Habet used for habitat.

care.

157. Recepit, either he got back, or he retained. back building.

160. Juxta--cum mea, exactly the same as my own (daughter). 161. Rogaturu's, abbreviated for rogaturus es.

163. Argutum. The word is applied to a man, "qui semper arguit,"

"who is always wrangling," and may be translated spiteful, babbling. 165. Assidui, gossiping, who take every chance of sitting down together, and pulling their neighbours to pieces.-Scurras. This word had not at this period acquired the objectionable force which it had afterwards. At this time it was the usual term applied to the wits and fine gentlemen of the day.

166. Egomet-traho, I quite include myself among them, I am just as bad as any of them, because I have lent an ear to their lies.

169. Habiturust, for habiturus est.

173. Falsone, they do not care the least (lit., a lock of wool) whether their indiscriminate praise or blame of any one be false or true.-Quem

velint is the object of the two verbs laudent, culpent.

174. Dum illud-sciant, provided only they know what they please to know. 177. Evortisset, old form for evertisset.

179. Prosilui-castigatum, I started forth to accuse. after a verb of motion.

Supine in um 182. Famigeratori res sit, the talebearer were to be held responsible and suffer damage and loss. A very similar idea is to be found in Sheridan's "School for Scandal," where Sir Peter Teazle expresses his wish that there was a law passed to punish the originators of all scandalous stories :

"Mrs. Candour. But surely you would not be quite so severe on those who only report what they hear?

"Sir Peter. Yes, madam; I would have law merchant for them too; and in all cases of slander currency, whenever the drawer of the lie was not to be found, the injured parties should have a right to come on any of the indorsers."

184. Faxim, for facerim, I'll be bound.-Qui sciant, I'll be bound we should have very few knowing (i.e., saying they know) what they don't.

As a specimen of the powers of Plautus in a more serious vein, we subjoin from the same play the thanksgiving of Charmides to Neptune for his prosperous voyage :—

TRINUMMUS, ACT IV., Sc. 1, l. 1—8.
CANTICUM.-CHARMIDES.

Salsipotenti et multipotenti lovis fratri ætherei, Neptuno,
Lætus lubens laudes ago, et gratis gratas habeo, et fluc-
tibus salsis,

Quos penes mei fuit potestas, bonis meis quid foret et meæ vitæ,

Quom suis me ex locis in patriam urbis tutelam reducem faciunt.

Atque ego tibi, Neptune, ante alios deos gratis ago atque habeo summas.

Nam te omnes sævom, severum atque avidis moribus commemorant,

Spurcificum, immanem, intolerandum, vesanum. Ego contra opera expertus.

Nam pol placidum te et clementem eo usque modo, ut volui, usus sum in alto.

NOTES.

sons have been led to deny this, because both the premises are not always expressed, one of them, indeed, being commonly omitted; but in every case it will be found that the admission of the second or suppressed premise is essential to the validity of the conclusion as an inference. This will appear evident from supposing the truth of the suppressed premise to be denied, when it will found that we have no sufficient grounds to warrant our inferring the truth of the conclusion. If, for example, any one asserts that from the single premise, "the world exhibits marks of design," he can draw the conclusion that "the world must have had an intelligent author," his error will be seen if an opponent denies that "whatever exhibits marks of design must have had an intelligent author." This will at once make it evident that it is not from one premise alone that the conclusion is inferred, but from two in combination, whether they are both expressed or not. Any other example of syllogism which might be taken would equally illustrate this. Where, as above, one of the premises is suppressed, the argument is called by logicians an Enthymeme, though this is not the correct use of

the term.

When a syllogism is stated in correct logical form, the premises are placed first, and the conclusion last; the latter being, in all cases, that which is to be proved, and the former that by means of which this is proved.

There are several kinds of syllogisms, differing in the kinds of propositions of which they are composed; but we are at present speaking only of the Categorical Syllogism, all three propositions of which are pure categoricals.

Let us take a syllogism of this sort, and examine and analyse it, e.g.:

All men are mortals;
Socrates is a man;

Therefore, Socrates is mortal.

Hence, of course, it is not even necessary, in order that we should be able to determine upon the validity of a syllogism, that we should understand fully the meaning of the terms of which its propositions are made up; so that we can just as well represent such a syllogism as the above by means of symbols without any fixed meaning. "All Y is X; Z is Y; therefore, Z is X," will be a correct and valid argument, no matter what X, Y, and Z may be employed to represent.

The rule for testing the validity of syllogisms, laid down by Aristotle (and called the Dictum de omni et nullo), is this:Whatever is predicated (i.e., affirmed or denied) universally of a term (in other words, of a term distributed), whether affirmatively or negatively, may be predicated in like manner (i.e., affirmed or denied), of everything contained under it." Thus,

in the examples we have taken, "mortal" (X) is affirmed universally of the term "men" (Y), i.e., of this term distributed, and "Socrates" (Z) is contained under " men (Y); therefore "mortal" (X) may be affirmed of "Socrates " (Z). This rule may be applied immediately or ultimately (as we shall after