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Man glaubt, er sei gefallen.
It is thought he has fallen. the frontier. 5. He asserted that it was better to stay at home Sie glaubten, ich sei frank gewesen. They thought I had been sick. than to go out. 6. I wish that he may be treated with more Man glaubte, ich wäre nie da ge- It was thought I had never been kindness. 7. He tells every one that you are a very rich man; wejen. there.
but if you were, you would not be so penurious. 8. Have you Er glaubt, er werte nie wieder glück. He believes he shall never be heard, too, that your friend has fallen from his horse ? 9. No, licy terten. happy again.
but I have heard that he has fallen out of the coach. 10. I hope Man sagt, fie werte bald die Ober. It is said she will soon have the that you will be with your parents in a fortnight. 11. I doubt band haben. ascendancy,
that he can be so ungrateful. 12. This stranger says that he VOCABULARY.
has been twice to India, and was very sick on his last voyage. Allgemein', universal, Fallen, to fall. Rufen, to call. universally. Geschich'te, f. history. Tod, m. death.
LESSONS IN GEOMETRY.-XII. Barba'tijd. barbar- Grenze, f. frontier, Ueberschrei'ten, to cross, As the next lesson will put the learner in possession of the last ously. Jzerbciójühren, to pro
pass over. Behaup'ten, to assert, duce, bring on. Ungarn, n. Hungary.
of the problems that we intend to give on the construction of allege. Langsam, slow, slowly. Verfah'ren, to act,
figures contained by three and four straight lines—namely, the
triangle, the square, the rectangle, and the parallelogram----we Dre'figjährig,of thirty Melten, to announce, proceed. years.
would recommend him to go carefully over the whole of the prestate.
Verstellung, f. dissi. (in'geben, mindful. Ner'venfieber, n. ner- mulation.
sent series of problems from the commencement, constructing as Gro'bern, to conquer.
many figures as he possibly can, to meet the requirements of the
data in each case. Grzählen, to tell, nar. Ober, upper. Zwar, indeed, it is
And in doing this we advise him to try to rate. Rom, n. Rome.
construct figures different in form to those which we have given
in these pages, as, if he can do this, he may be sure that he has RÉSUMÉ OF EXAMPLES.
gained a thorough knowledge of the various methods of conOr bebaup'tet, taß es war sei. He asserts that it is true. struction set forth in the different problems. 3d till, daß Du spar'samer seiest. I will that thou be more frugal. The problem in practical geometry that was brought before the Gi imeint mir, daß er traurig ist. It appears to me that he is notice of the student in the last lesson, showing him how to
construct a square that shall be equal in superficial area to the Man glaubt, taß wir reich seien. It is supposed that we are rich. sum of two squares described on two given straight lines, has Cbgleidh' ihr Fremte seit, so seid ihr Although you are strangers you given him the key to the construction of squares, rectangles, tody willfom'men.
are nevertheless welcome. and parallelograms, equal in superficial area to the sum or fi scheint mir, tag sie Amerika'ner It appears to me that they are difference of any two or more squares, rectangles, or parallelofint. Americans.
grams, as the case may be; and it has also shown him that the Es sieht aus, als ob er nicht gesund' He appears as though he were main principle on which their construction depends, is the relation wire. not healthy.
between the triangle, the figure contained by the least possible 3d glaube, daß er frank gewe'sen ist. I think that he has been sick. number of straight lines (since two straight lines cannot enclose Man jagt, taß er schon hier gere'sen They say that he has already a space, although one curved line can, as in the case of the circle), sci. been here.
and all regular figures contained by straight lines-namely, the Ich hoffe, baš tu glüdlich gewesen I hope that you will have been square, the rectangle, and the parallelogram. It may be as well sein wirft. fortunate.
to repeat that this principle is, that when a square, rectangle, Er sagte mir, tap tu tas Buch des He told you had the or parallelogram is upon the same base and between the game Sehrers habest. teacher's book.
parallels, the area of the square, rectangle, or parallelogram 3d bezweifle, tas der Jäger die Flinte I doubt that the hunter has the (as the case may be), is double the area of the triangle. gun.
Now supposing we have a square, rectangle, or parallelograna Man vermuthet, tas ikr viel Geld It is supposed that you have before us, and we wish to construct a triangle equal in area to habt. much money.
either of these figures, what have we to do? Manifestly nothing Nan weiß das sie Freude an dieser It is known that they have more than to draw one of the diagonals of the figure in question, Cadre haben.
pleasure in this affair. produce the base indefinitely in the necessary direction, and, Ich körte, taß er ein großes Ver. I heard that he had a large after setting off on it a straight line equal in length to the side morgen bätte. fortune.
of the square, rectangle, or parallelogram, that serves as its Ter Onkel erzih'te, taś cr cine an's The uncle said (narrated) he base, to join the extremity of the line thus set off with the gcachme Reise gehabt habe. had had a pleasant journey. upper end of the diagonal. This will be evident on an inspection EXERCISE 80.
of Fig. 42, where, in the square (rectangle or parallelogram)
A BCD, the diagonal a c is drawn; the base CD, on which the 1. Haben Sie auch gehört, ich sci vom Pferde gefallen? 2. Nein, ich
square (rectangle or parallelogram) A B C D stands, is produced bitte, Sie seien aus tem Wagen gefallen. 3. Die Geschichte meldet, tak indefinitely in the direction of F; a straight line, D E, set off Tilg, welder Magdeburg im treißigjährigen Kriege eroberte, sehr barbarijch along it from the point D, equal to DC; and the straight line merjahter sci. 4. Mein Bruder jagte, Sie seien sehr gelobt worten. 5.
E A drawn, joining the points E and A, and completing the triangle Die franzosen behaupten, sie seien tie Gebiltetsten in der Welt. 6. Ihre A E C, which is equal in superficial area to the square (rectangle Sowefter glaubte. Sie wären in der Start gewesen. 7. Die Engländer
or parallelogram) A B C D. faut ter Meinung, sie seien tic Herren tes Meeres. 8. Dieser Reisente er,
And, conversely, when we wish to draw a rectangle or parallelozahlte, et sei zweimal in Rom gewesen. 9. Er hefft, er werbe in acht Tagen gram equal to a given triangle, all we have to do is to bisect in Dreåren sein. 10. Sie fürchten, Sie seien zu langsam im Handeln gewesen. the base of the triangle, and on either half of the base construct 11. Wir glaubten, Sie wären auf tem lante. 12. Ich glaube, wir waren the required rectangle or parallelogram, after drawing through gestern zu Guch gekommen, wenn das Wetter schöner gewesen wäre. 13. Id the apex of the triangle a straight line parallel to the base. In glaubte, er wäre der warnenten Stimme seiner Eltern eingerent gewesen. the case of the rectangle, after bisecting the base of the triangle14. Er sagte zwar, er sei franf, aber Viele behaupten, es sei Verstellung as, for example, in Fig. 43, where the base of the triangle a BC ron ihm gewesen. 15. Seine Verwandten sagen, sein Glück habe sein is bisected in D-and drawing a straight line, PQ, of indefinite Unglüc herbeigeführt. 16. Ich hörte mit Berauern, Sie hätten das length, through the apex A of the triangle A B C parallel to its Nertensieber gehabt. 17. Da ich in dem obern Zimmer war, hörte ich Sie basBC, a rectangle equal in superficial area to the triangle aucht rufen. 18. Man erzählt, ter Ungar habe bis in den Tod sein Vater
A B C is formed by drawing the straight lines C E, D F through lant treu pertheidigt. 19. Ich hörte, dieser junge Franzose werde ein großes the extremities c and D of CD, one-half of the base B C, perpenbermögen etben. 20. Ich glaube, daß viele Menschen hier auf Erden ihr dicular to B C, and meeting P Q in E and F; or by drawing the Cutes gehabt haben werden.
perpendiculars DF, B G, through the extremities D and B of BD, EXERCISE 81.
the other half of the base meeting P Q in F and G. 1. People say these gentlemen have been tipsy, but they are In the case of the parallelogram, if it be required to make two mistaken. 2. They say that residence in Paris is moro agree- of its opposite sides equal to a given straight line, as the
straight able than in London. 3. We could not believe that this was line x in Fig. 43, or two of its opposite angles equal to a given trae. 4. It is universally believed that the enemy has crossed angle, as the angle y, we must from the extremity of one-half
of the base of the triangle-say, for example, the extremity D of and on the straight line D E set off D F equal to the side the half cd of the base—with a radius equal to x, describe an DA, or Bc of the rectangle A B C D. Bisect ce in G, and arc cutting P Q in H; join D h, and through c draw C K parallel from G as centre with the radius G C O G F describe the semito D H, and meeting p q in K, thus completing the parallelogram circle cu F. Produce D A until it meets the arc car in K. IDCK; or, at the point c in the straight line D o we must Then along the straight line D C set off D L equal to D K, and
through the points K, L, draw the straight lines KM, LM parallel to CF, D K respectively, and meeting in the point n. The figure DLM K is a square, and it is equal in area to the given rectangle A B C D. If F NOL had been the given rectangle, the same process would have been followed. FL
would have been produced in the direction of L, and L c set off Fig. 42
on it equal to the side L o of the rectangle LONF; C F bisected
in g; the semicircle C I F described as before, and L o produced make the angle DC K equal to the given angle y, and through to meet the circumference C HF in P. The square drawn on LP D draw D H parallel to c k in order to complete the parallelogram is equal in area to the rectangle F LON. as before.
If it be required to draw This process will only be found practicable for the construction a square equal in area to a of a square equal in area to a triangle when the triangle is a given parallelogram, we have right-angled isosceles triangle; but for any other description of only to constructa rectangle triangle it will be found necessary first to construct a rectangle equal to the given paralleloequal in superficial area to the given triangle, and then to draw gram, and proceed as above. a square equal to the rectangle thus obtained. How to do this This will be seen from Fig. will be shown presently in Problem XXXI.
45, in which the rectangle By Problem XXX. we are enabled to construct a square equal in A B C D is equal to the
Fig. 45. area to any number of given squares. Thus, suppose we wish to parallelogram D C Q R. construct a square equal in superficial extent to the five squares PROBLEM XXXII.-To draw a rectangle that shall be equal of which the length of the sides of each is represented by the to a given square, and have one of its sides equal to a giren straight lines A, B, C, D, E respectively (Fig. 44). Draw any straight line. straight line, F G, equal to A, and at its extremity, G, draw G H Let ABCD (Fig. 46) be the given square, and x the given side at right angles to it equal to B. Join F h: the square described of the required rectangle, and in this case let x represent the
on Fh is by Pro- shorter of the two pairs of sides by which the rectangle is enclosed. blem XXX. equal to First produce c d indefinitely both ways towards E and F, and the squares de- along c E set off co equal to x, and also along C B set off c H scribed on fo and equal to x. Join B G, bisect it in K, and throngh K draw K L per
Next draw pendicular to BG, meeting E F in L. Then from the point L as I k equal in length centre, with the radius L G, describe the semicircle G B M. to the given line c, Through the point m draw n parallel to A D Or C B, and
at right angles to through a draw I n parallel to A B or E F, and let the lines Fig. 43.
HF. Join KF. The HN, M N meet in n. The rectangle cun x is equal in area
square described on to the square A B C D. F K is equal to the squares described on K H, A F, or to the When the longer of the two pairs of sides that enclose the squares described on K H, H G, G F, since the square described rectangle is given, as Y in Fig. 46, produce c d indefinitely on F is equal to the squares described on H G, G F. By con- both ways as before, and set off c » along C F equal to 1. tinuing this process we at last obtain the straight line m F. The Join B M, bisect B u in o, and through the point o draw o L at square described on this line is equal to the sum of the squares right angles to Bm, meeting E F in L. Then from L as centre, described on the given straight lines, A, B, C, D, E. Now let us with the distance L m, describe the semicircle M BG. Set off see how far this is of practical value to the artisan. Let us along o B the straight line cu equal to CG, and complete the suppose that a cabinet-maker has a number of small squares of rectangle cun m by drawing H x, m n through the points 1 and veneering of several kinds of choice wood, each square being a parallel to c m and cu respectively. of a different size, and he wishes to use up this wood in veneer. The learner must remember that the side of a square is a ing a table or the panel of a cabinet without wasting a single mean proportional bescrap of it. By following the process just described it is manifest tween the sides of any that he possesses the means of readily ascertaining the exact rectangle that is equal to area of the square that these pieces will cover, and after find it in superficial area; and, ing this, he can, if it be desirable, by Problem XXXI. draw a therefore, that to find the rectangle equal in area to the square if he prefer this form for length of the side of a using up his squares of veneering, and then arrange his pattern square equal to a given
in such a manner that his squares rectangle, we must set off
ferent sizes. Of course in such tion to meet the semicircle, as in Problem XIII. (page 193); Fig. 44.
cases the operator would work to while, to find the lengths of the sides of a rectangle that shall be
a given scale, and the process equal to a given square, we must draw a straight line at right might be used as a test of the correctness of the result of the angles to a line equal in length to the side of the square, and operation by which the whole content of the squares may be from a point in this line on either side of the line that repre found arithmetically, or as one which is far more certain and sents the side of the given square, draw a somicircle with a involves far less trouble than the arithmetical operation, which radius equal to the straight line joining the point that is used would be a long and tedious one.
as the centre of the semicircle and the more remote extremity PROBLEM XXXI. — To draw a square that shall be equal in of the line that represents the length of the side of the given superficial area to a given rectangle.
square. The lines intercepted between the other extremity of Let ABCD (Fig. 45) be the given rectangle; it is required this line and the extremities of the arc of the semicircle will to draw a square equal in superficial area to the rectangle be equal in length to the sides of a rectangle, having a supra A B C D. Produce c = indefinitely in the direction of E, ficial area equal to that of the given square.
ANIMAL PHYSIOLOGY.-XII. managed that the eye is completely imposed upon, and it is
almost impossible to believe that the surface is flat. A rapid THE ORGAN OF TOUCH (concluded).
sweep of the hand, however, at once dispels the illusion; and It has been shown in the previous lesson that the sense of so effectually that when you move back to gaze again, it is diffi. touch, in its wider sense, is of a highly intellectual character. cult to regain the impression of an embossed surface. The As an informant of the mind it is second only to the sense unbelieving Thomas, however reprehensible his scepticism might of sight, and in the suggestion of abstract ideas it is, perhaps, be, expressed it both with force and delicacy; for he at once superior even to vision itself. There is no fundamental con recognised that his own sense of sight might be deceived, and ception in relation to matter which it cannot impart. Though expressed a doubt, not of the truthfulness of the other disciples, devoid of every other sense, a man possessed of this can pursue but of their correctness of vision. the study of every science, if he will but surmount the diffi. That this sense, when combined with the muscular sense, is
I. OBBAXS OF TOUCH OF VERTEBRATA :-1, HEAD OF A SNAKE; 2, HEAD OF AN OSSEOUS FISA--MOTELLA ; 3, HEAD OF A FISH–GYMNOLABES,
SHOWING THE TENTACLES. II. ORGANS OY TOUCH OF MOLLUSCA:-1, AMPULARIA (APPLE-SNAIL), SHOWING TENTACLES ; 2, PLUMATELLA REPEXS, SHOWING THE TENTACLES. III. ORGANS OF Touch OF ARTICULATA :-1, CARABUS VIOLACEUS (THE VIOLET CARNIVOROUS BEETLE) — (@) AXTENXE, (6) MAXILLARY PALPI; 2, ENLARGED VIEW OF UNDER PART OF HEAD, (c) LABI PALPI ; 3, ENLARGED VIEW OF LABI PALPI ; 4, LABROM, OR UPPER LIP; 5, MANDIBLES, UPPER OR BITING JAW; 6, MAXILLA, WITH ITS PALPUS OR LEFT LOWER JAW WITH ITS TEELER. IV. ORGANS OF Touch or CELENTERATA AND PROTOZOA :—1, ANTHEA (SEA-ANEMONE), SHOWING TENTACLES ; 2, ACTINOPHRYS, SHOWING THE PSEUDOPODIA,
culties which oppose themselves to his acquisition of the results of a highly intellectual character, does not at all contradict the of the experience of other men. Thus, blind men have taken statement that it is also the simplest and most rudimentary of to the study of mathematics, and by the aid of the figures of the senses. That it is simple and rudimentary agrees well with Euclid, conic sections, etc., given in relief, have acquired a the fact that satisfactory evidence may be found of its existence knowledge which has placed them in an honourable position in in most animals. The possession of this sense reaches far the examinations at Cambridge. The very theory of light and lower down in the animal scale than that of the other special all its laws are quite comprehended by such blind students. The senses. Definite organs of touch are well developed in animals sense of touch is absolutely bounded by the surface of the body, in which no other organs of sense are found ; and the power of but it makes amends for being less far-reaching than other extemporising feelers, or prolongations of the body into fingers senses by being the most real of all the senses. We make our or filaments, is a character of the very lowest animals with ultimate appeal to it when the eyo gives false or confusing which we are acquainted. Reflection would tell us that this indications. In the King's Palace at Amsterdam there is a surface sense is almost essential to animal life. How necessary wainscot painted to express figures as if they projected from, must it be for every animal that moves or feeds to know the and were carved, upon its surface. The shading is so well exact limits of its body—the confines of the domain over which
it has control ; what is part of itself, and therefore has to be ' illustration in Lesson XI. (page 353) to understand the structur: nourished, cherished, and defended--what is foreign, and there. ' and relation of each hair to the skin in which it is developed and fore may be used or avoided, as it is wholesome or noxious. , fixed. The hair is essentially a tubular projection of the cuticle, Indeed, the sense seems indispensable to all animals that are firmer and denser in its composition, being made up of closelynot plunged and fixed, through every stage of their life, in the pressed, elongated, spindle-shaped cells, instead of scale-like, midst of a medium which is both air and food to them--to all easily-detached ones. It is not, however, produced from the animals, it might be said, if it were not tautological, whose life level of the surface of the body, but from a bag or follicle, which is not purely vegetable.
is always narrow, and more or less deep as the hair is long or In the higher animals, and in all those whose means of defence short. This horny tube dilates at the bottom of its bag to lie more in their active powers than in defensive armour, the enclose a vascular papilla, similar in every respect to those sense of touch is distributed over the surface of the skin, as in papillæ which lie immediately under the surface of the superman. Every such animal may be compared to an island. The ficial cuticle. The hair itself, like the rest of the cuticle, is boundary of its body is the coast-line. Along the whole of this without sensation, as indeed it must be for the comfort of the are placed, at various intervals, places of out-look, just as our animal; but the papilla has not only blood-vessels but nerves, own tight little island has been surrounded with Martello and is very sensitive, so that the hair cannot be pulled or moved towers. These stations are few and far between where the in any direction without affecting the sensitive part. Though a coast is rocky, abrupt, and inaccessible, but nearer together furred animal cannot precisely tell the exact point at which it is at those parts where a descent could be easily made, and touched, on account of the length and flexibility of its individua erowded together at the outlets of ports, creeks, and river. hairs, yet the sensation of touch is as truly conveyed to the true mouths, through which an active commerce is carried on. The skin, as it is when the pressed ridges of the forefinger of man comparison of the extremities of the tactile nerves to Martello cause feeling to be excited in the papillæ beneath them. In one towers is the more appropriate, because these have ceased to be respect hairs are even advantageous to the sense of touch, inas. of any use in defence, and have become stations of out-look for much as they reach considerably beyond the surface, and thus the coast-guard. So the tactile nerves are, in themselres, no the range of the sense is extended. This advantage is so far protection, but rather, being delicate organs, they need protec- recognised by nature that certain hairs are specially developed tion; for they act as alarmists, awakening and calling up the active which have no other use than that of touch. These may fairi powers to fight in defence of the common country. These two be described as tactile organs. These hairs are usually, and functions of the skin-namely, that of passive defence and active almost exclusively, situated in the upper lip, projecting from the alarm--are complementary to one another : where one is very most prominent part of the muzzle. In quadrupeds the sout efficient, the other is less needed. In the scaled and mailed is of course the most salient part of the body, and is most used fishes, and in such forms as the tortoise among reptiles, and the in investigation. These whiskers, as they are called (though armadillo among animals, the function of sensation is sacrificed they would be better named moustaches), are remarkable for to that of defence; but in the naked skinned animals the sense their length and stiffness, the depth to which their large bulbs of touch had need be very acute. In comparing man with the run into the skin, and even protrude in the internal surface, and lower animals of that class to which he belongs, we find that also for the large nerves that enter the papillæ of the bulbs. his sense of touch is, perhaps, better developed than that of any Those coming from the whiskers of a seal as they run together other animal. The lower animals have to sacrifice a certain look like the strands of small cords as they become woven into amount of their surface sensibility to the paramount necessity a rope of tolerable thickness. The animals in which these of being shielded from the cold; or, to put it more truthfully, whiskers are most developed are the carnivora and the rodents. to the retention of their animal heat. Man has neither the This is not improbably associated with the fact that these are continuous thick coating of hair of the ox, the thick skin of the for the most part nocturnal animals. Moreover, many of the rhinoceros, nor the dense accumulation of fat below it which is rodents inhabit holes in the ground, trees, etc.; and many of found in the pig and in the whale. He is only cosmopolitan the smaller carnivora are always poking about in holes and because his superior intellect enables him to clothe and house crannies for prey. It certainly would be an advantage to a for himself. His nearest relatives among beasts, though much on a dark night to be able to gange with his whiskers the size better supplied with hair than himself, are confined to the of the aperture in a hen-roost before he tried to force his way tropics. Man makes himself at home everywhere, but only by through it; and thus it has been thought that there is a relabecoming a "clothes philosopher.” His triple investment of tion between the width of the body and the extreme extent of ordinary, nether, and over clothing, prove him to be an exotic the whiskers.' species. He supplements by art the line of defence at those In birds the place of hairs is supplied by feathers. The stron points where nature has left him exposed. The main use of the ture of these is very wonderful and beautiful, but a description. coating of hair is, no doubt, to defend the brute from the winter's of it would be out of place here, because they are certainly lase cold, but that which will keep in the heat will keep it out, so efficient tactile organs than hairs. Birds' feathers are coarse that it may also be considered as a defence against the excessive than hairs ; they are less flexible; they are inserted only on cerheat of the sun also. Doubtless the universal presence of hair on tain parts of the body; and since there must be provision made the heads of both sexes of the human species indicates that in for moulting, they are more definitely cut off from the sensitive his native home man had more to fear from sun-stroke than skin below. For all these reasons they are not good organs for from the cold of winter. Besides this, the hair is sometimes a transmitting the sense of touch, although they are formed in real defence against the rough usage of the outer world. Thus the same manner as hairs. Probably on account of this inapthe manes of the lion and the buffalo are real shields both against 'titude to transmit impressions, they are sometimes replaced by trenchant blows and the worrying of the teeth of hostile animals. hairs in certain parts of the body; but as a rule the whole of the Even the matted hair of the negro is said to be able to resist a bird's body is encircled with feathers, which lie overlapping one tolerably forcible sabre cut. The principal use, however, is, another, and turned in one direction towards the tail of the bird. doubtless, to defend from cold; and it is remarkable how this in the same manner as tiles on a house-roof. A bird's jams, main object is arrived at without much prejudice to the function instead of being covered with soft, flexible and sensitive lips, of touch.
are covered with a hard, horny bill, and its legs, though ofter Few solid substances are lighter than hair, even when pressed devoid of feathers, have to be defended by scales or scutes, to close ; and few substances are worse conductors of heat--so that prevent the long tendons of their leg muscles being severed brutes retain their heat by the aid of a substance which costs Under these circumstances, a bird enjoys little advantage fron them but little in the way of carriage. Beyond this, the springy, its sense of touch. Indeed, it is only in the padded under-surstiff, yet soft texture of hair, makes it always permeable to the face of the foot and toes, and sometimes in the beak and air ; and air, when motionless, is a bad conductor of heat, and tongue--when the former is leathery, and the latter not capped adds, absolutely, to weight. Hence on the coldest day, when with horn--where there can be any provision for the exposure the thermometer stands below zero, the beast is still surrounded of a sensitive surface. It has sometimes been stated that the with a layer of warm air, almost equal in temperature to its body. i heron, as he stands in shallow, muddy water, is guided by feeling So much to prove its efficiency for its main purpose. Now we the eels twisting in and out, or even sucking his toes. This have to show how it leaves the sense of touch, if not unimpaired, statement seems rather suited for a fable of the biter bitten at least not obliterated. The reader must refer back to the than to be regarded as a scientific fact. That the sense is present in some birds is shown by the fondness of parrots for tickling; which was blind when caught had obtained its food so well by but it may be stated that the great activity of birds makes them the aid of this that it was quite in good condition. Barbules are rely on their far-ranging senses rather than on the circumscribed well adapted to the purpose of touch. If in any other way indications of the sense of touch.
nerves were conveyed through the scaly covering and exposed, The cold blooded animals (reptiles and fish) differ from the these delicate structures would be liable to be injured by the warm-blooded (mammals and birds), in having for the covering impact of hard external bodies, which would be crushed between of their bodies no non-conducting or heat-retaining substances. them and the hard and underlying scales; but since the main Hairs and feathers are admirable retainers of heat; but scales nerve of these barbules accompanies a cartilaginous core, and and scutes, though good to resist blows and pressure, allow heat since it springs from a single point to be spread upon a flexible to pass out or in without much resistance. This, of course, is pillar which hard bodies would drive before them, the chance of associated with the fact that reptiles and fish have but little having the nerve crushed is much reduced. Barbules are for heat to lose. It does not follow, however, that because the the most part found on the jaws of grovelling fishes like sturbody of a fish or lizard is entirely defended by scales, whose free geons and barbels, which feel along the bottom for all kinds of edges overlap the insertions of those next behind them in a garbage which may have sunk there. manner which is called “ imbricated,” that therefore they are The mollusca have received their name from their general entirely without the sense of touch. The scales are developed character of softness; mollis being the Latin adjective for soft. much as the human nails are, and we know that these are them. This name was given them by Cuvier to contrast them with the Belves insensible; yet they are so intimately connected with hard-coated insects and crustacea which belong to the subthe sensitive parts by which they are formed, that the nails are kingdom articulata. Hence in those species which are not prothe conductors of acute, and even morbid sensation. The quick vided with a shell, and in the exposed parts of those species of the nail is proverbially sensitive to pain; witness the common which have this protection, there is a soft, sensitive skin. The phrase of being wounded, or cut to the quick. Reptiles, how. skin, however, in this sub-kingdom has often superadded to the ever, slough at certain seasons, and the old skin, dissevered functions which it possesses in vertebrata the functions of respi. from the cutis, adheres to them for some time---in fact, until a ration and of locomotion. Even those parts where the sense is new and complete armour is formed below. During such periods, more or less localised have so many other offices to which the and inferentially at all times, the sense of touch cannot be sense is secondary or subservient, that it would lead us too far acute. Scaled reptiles may be alive to blows or pressure, but from our subject to describe them. It is true that the gastero. hardly to those sensations of soft touch which convey the most poda have horns as special tactile organs; but we find in the distinct impressions of all to us. These remarks apply with yot cephalopods the sense of touch is intimately combined in the more force to the hard, stony, surface of the backs of crocodiles. arms with the elaborate apparatus for grasping and holding their The under side of the body of crocodiles is leathery rather than prey; and in the brachiopods the sense is united with the organs stony, and has fewer stony masses on its surface, and this is for breathing and keeping up currents in the water. We must, therefore sensitive. Sir Emerson Tennent gives an amusing therefore, avoid going into details in reference to them. It may account of & cayman, which he surprised before it could make be stated generally, that the slower an animal moves, and the its retreat. The Ceylon crocodile threw itself on its side, and more fixed its station, the more will its sense of touch be devefeigned death ; but when it was tickled under its arm it found loped in proportion to the other senses. Hence the sense of the process too much for its gravity, and finally got up and touch is well developed throughout this sub-kingdom. Soft hobbled away. As we before remarked in the article on taste, bodies are ill-suited to energetic motion ; but soft bodies are the tongue is made use of by serpents and lizards to touch well adapted to receive tactile impressions. In those animals objects with; and this is probably its main, if not its only use. of this sub-kingdom which are wholly fixed, the organs of touch In conformity with the assertion that nocturnal animals often are multiplied; and in the lowest class of all there is a horsehave specially modified organs of touch, we find that certain shoe-shaped or circular series of tentacles round the mouth, nocturnal tree-snakes have their snouts prolonged into tactile which are extremely sensitive. This arrangement of feelers organs.
around the mouth is so general a character of fixed animals, The large majority of fish are completely closed in by plates that there is a striking similarity between the outward form of and scales. With few exceptions even the lips are hard and these lower molluscs and the fixed animals of the sub-kingdom dry, so that they need to have some special organs of touch. cælenterata, although the essential organs are quite different. Sometimes certain rays of the fins are detached from the oar- The articulata (though some of them are soft-skinned) are for like parts, and become long styliform organs of touch. When the most part covered with a hard, horny covering, which is as this is the case, they are clothed with soft parts, which are well resisting as plate-armour. It is therefore necessary that these supplied with nerves. Thus, in the gurnet three soft rays aro animals should have special organs of touch. We have already told off from the front of the pectoral fin, to form fecling referred to those of the lobster and its tribe in a former number. fingers. It is curious that in a creature so far removed from Insects have, developed from their heads and mouth-organs, man we have the same parts modified to the same use, though jointed rods, which have nerves of touch running to them and in almost all the intermediate animals this part has a different up into them. These jointed rods are covered with hard, horny function. In the angler two rays detached from the back fin, matter, like the rest of the body; but sometimes the last joint and situated on the top of the head, have this function, but the exposes a naked membrane, and where this is not the case, the tise to which he puts these feelers is remarkable. One of the jointed and therefore flexible nature of the organs make them feelers has at its end a flattened, shining, and flexiblo adjunct, capable of receiving impressions of touch, and of measuring the and this is used as a bait, just as a silver strip is used by the dimensions and resistance offered by external objects. The troller. The angler is rapacious, but sluggish; he therefore normal number and position of these organs will be seen in the her on the bottom, with his huge, ugly mouth wide open, and illustration. There are two long, many-jointed ones jutting from Etirs up the mud with his fins to conceal himself, while he the head; these are called the antennæ. Another pair (or pairs) drops his sensitive bait before his mouth and keeps twitching it spring from the lower lateral jaws; they are called the maxillary aboat, until he feels some hapless fish begin to nibble, when he palpi. Another pair (or pairs) spring from the sides of the makes a forward rush and closes his mouth upon him. The lower lip; these are called the labi palpi. The soft-skinned whole of each of the four limbs of the lepido-siren are converted spiders have no antennæ or labi palpi, but their maxillary palpi into organs of touch. For the most part, however, the limbs of are so long and large as to look like legs. teh which correspond to our legs and arms are entirely devoted Tho echinoderms, or sea-urchins, are so enclosed in their more to locomotion, while quite new structures are developed for them or less spherical boxes of hard shell, that a casual observer would to feel with. These special tactile organs are called barbules. suppose them to be unfeeling wretches, capable of inflicting They are placed on the head, and generally at the fore part of wounds with their long spines, but insensible to softer emothe jaws. When on or under the lower jaw they may be single; tions. This is not the case, however, for they can protrude bat they are more often, and when on the upper jaw always, in through the small holes which perforate the shell and occupy five pairs. Two instances are given in the illustration: the one double meridional bands of their globular boxes, a multitude of shows how they occur in an eel-like fish, and the other in an soft, tubular, sucking feet, to each of which there runs a nerve. ordinary-limbed fish. The single medial barbule under the ja: The sea-anemone, with its streaming feelers, lives by feel. of the cod is a familiar example. It is supposed that a cod ing; and the whole sab-kingdom to which it belongs is