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ANIMAL PHYSIOLOGY.-XI.

THE ORGAN OF TOUCH.

THE sense and organ of touch have been placed last in the list, because we have been all along proceeding from the more special to the more general sensations. The retina of the eye is specially modified and set apart to receive and interpret the light. Light has neither meaning nor effect when applied to other parts of the body; and the retina is out of the reach of other kinds of contact, and is quite insensible even to great heat, as Professor Tyndal has shown experimentally. The ear appreciates the aerial waves which are otherwise unknown. The nose and

When any part is disordered, a general feeling of depression cannot be shaken off. The sense of touch is allied to this general consciousness, but it differs from it in that its impressions are distinctly referred to the parts from which they proceed-the mind is able to localise them with precision. With regard to the locality of the impressions which proceed from the viscera, we know but little except by reason. Hence ignorant people will refer maladies very wrongly. Thus we hear of heartburn and stitch in the side. Nervous people will attribute rheumatic muscular pain to the lungs, stomach complaints to the heart, and lumbago to the kidneys. This wrong reference is made even when the pain or inconvenience is occasioned by a

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1. SECTION OF THE HAIRLESS SKIN (MUCH MAGNIFIED). II. SECTION OF THE HAIRY SKIN (MUCH MAGNIFIED). III. TIP OF THE FOREFINGER. Ref, to Nos. in Figs. I., II.-1, epidermis or scarf skin; (a), superficial layers; (b), rete mucosum. 2, cutis or vascular skin. 3, subcutaneous layer, composed of fibres, enclosing-4, sweat glands; and 5, fat cells. 6, papillæ. 7, hair bulbs and their papillæ. 8, 9, nutrient arteries. 10, oil glands. 11, hairs.

mouth, though they are less exclusively devoted to smell and taste, and not so specially modified to receive these impressions as are the foregoing organs, yet their special sensations are peculiar. The sense of touch is more akin to what may be called common sensation, or general consciousness, and the organ is more widely extended and more intimately connected with other functions than the organs of the other sensations. If the eyes were closed, and no objects presented to the senses of hearing, taste, or smell; and if, further, the body could be floated in a liquid of such temperature and consistence as to present to the mind no sensation of contact, there would still doubtless be a general consciousness of the existence of the body, not only as an intellectual deduction but as a sensation. This sensation forms an indissoluble link between mind and body. When all goes well there is a feeling of pleasurable existence, which may be called general and massive, rather than special or intense.

VOL. I.

mechanical cause, as by distension or pressure; but directly the cause of these obnoxious sensations reaches the skin, we can at once fix on the locality. Thus we learn that the sense of touch is distributed over the surface of the skin, and to those extensions of it which proceed from it to line the interior of the passages leading from the exterior of the body. The organ and sense of touch does not go far as we proceed into the interior of the body by these passages. Thus the throat is only sensitive to touch at its top part. The sensation of heat and cold proceeds further down towards the stomach, and below this all localised tactile sensation ceases.

In describing the organ of touch, we must therefore explain the nature of the integument and its appendages, although in so doing we are aware that this integument has many other functions, and is intimately blended with other structures which have nothing to do with the sense, but which we are compelled to notice.

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The skin consists of two layers. The outer one is called the cuticle or scarf-skin, and the deeper layer the cutis. The cuticle has neither blood-vessels nor nerves, but consists of cells which are formed at its inner surface (where it lies on the cutis or true skin), and are pushed outward as fresh strata are successively formed below them. When first formed, these cells are filled with fluid; they are oval, and longer in the direction perpendicular to the surface than in the other. As they are thrust outward, they become flattened in the contrary direction, so that at the surface they form dry, transparent layers, which are capable of being shredded off and stripped away in scaly or scurfy fragments by the ordinary wear and tear to which the outer surface is subjected.

The office of this part of the skin is simply protective; and in relation to this office of clothing and defending the blood-bearing skin, it is found thickest where there is the greatest friction, and thinnest where there is least. It is, however, thin everywhere, varying from of an inch in the palm of the hand to of an inch in less exposed parts. As, however, this scarf. skin is in continual process of being rubbed away, it is not only thicker in much-used parts, but is much more rapidly formed on those parts. Moreover, if any peculiar employments make the wear and tear excessive, unwearied nature still supplies the demand, and an excessive manufacture of fresh cells is stimulated from below. Thus, in the polishing of japanned articles it is found that no other fabric but the human cuticle is sufficiently delicate to produce the shining surface. The finest wash-leather would scratch; and hence women are employed to scour trays, etc., all day long; and yet they never wear down to the true skin so as to make the fingers sore, except during the first few weeks. The provision for the repair of this closely-fitting vestment is even carried beyond this, for if the whole cuticle be stripped off, so as to leave the cutis naked and sore, there is an immediate outpouring of fluid from the blood, which forms at once into a scarf-skin.

As this scarf-skin has no blood-vessels running into its substance, it has no means of self-repair; so that in proceeding from the deeper layers to the surface, the cells go through all the processes of birth, death, decay, and dissolution, though the membrane is so thin. Since, also, this skin has no nerves entering it, it has no sensation, and the sensation of touch must be felt through it in the same way-though in a much more perfect manner as we feel anything which touches us through our clothing. It will be seen, then, that it must fit very accurately and closely to the sensitive skin beneath, or the sense would be dull and imperfect. The skin below has an immense number of small hillocks, and each one of these is closely surrounded by, and inclosed in, the inner layer of the cuticle which is moulded upon them. When the cuticle is stripped off after being long soaked in water, it shows an infinite number of small pits, out of which the hillocks or papillæ have been dragged. If the whole be torn away before maceration, i.e., from the living skin, it usually tears away the papilla with it, leaving a bleeding surface.

In providing at once for the protection of the cutis, and also for the preservation of the acuteness of the sensation of touch, there is this difficulty: those parts which are most used to gain information by touch, are necessarily those which are most subject to friction. In such situations, then, the cuticle must be thick; yet a solid thick sheet would be liable to make us confound impressions made by two points near together which were in contact with the skin. There is a beautiful arrangement to obviate this difficulty, which is found in the cuticle of the tips of the fingers, palm of the hand, etc. Here the surface of the skin is seen to be thrown into small ridges and furrows, which run in curved lines parallel to one another, so that an impression made on the surface, or tops of the ridges, is only conveyed down to the papillæ immediately beneath it, and does not press sideways on those of the other ridges. A more minute examination of the tip of the finger with a lens, will show that these wavy ridges are subdivided into square-shaped masses by cross furrows, which occur at regular intervals, so as to leave the thickened part between of the same width as the ridge. Each one of the square-shaped masses has in its centre a little pit, which is the opening of a sweat-gland. No such definite arrangement of ridge and furrow occurs in other parts of the body, where the sense of touch is comparatively obtuse, or rather, not nicely distinguishing.

The cutis, or blood vascular skin, is tough and elastic, and consists in its deeper layers of interlaced fibres which hold in their interspaces little masses of fat, sweat-glands, oil-glands, and hair-bulbs, with hairs proceeding from these last to rise above the surface. It is also permeated with nerves, arteries, and veins. This, therefore, is a structure having all the endowments of life, and with the faculty of self-sustenance and sensitiveness. The true seat of the sense of touch is, however, its external portion, that which lies immediately under the cuticle. Towards the surface the fibres become closer and denser, and the various glands and fatty masses cease, while the blood-vessels and nerves are more numerous. In order to increase the touching surface, and to bring the nerve-threads closer to the exterior, the outer surface of the true skin is, as we have seen, raised at intervals into papillæ. Each of these is well supplied with vessels and nerves. Under the ridged surface of the palmar side of the hand, these papillæ run in lines corresponding to the ridges, there being two rows to each ridge, and sometimes smaller ones between. In other parts they are scattered irregularly, and are much fewer in number. That these papillæ are the true seats of the sense of touch, appears not only from the fact that nerves are traced into them, but because there is a strict relation between their number in a given space and the delicacy of the sense of touch in those parts. Thus in the space of one square line (of a square inch) there are 108 on the tip of the finger, 40 on the second joint, and only 15 on the last; and this decrease in number is in direct proportion to the sensitiveness of the surface to touch. Where the sense of touch is most acute and discriminating, little oval-shaped bodies have been found, one lying in the centre of each papilla, and these have been called the "little bodies of touch." It must not be supposed, however, that each of these papilla is capable of transmitting a separate impression to the brain, or that their office is simply tactile. Nerves do not enter all of them, and they are concerned in secreting the substance to form the cuticle. It would seem as though each nerve which conveys a single distinct impression to the mind, had a certain definite space of surface of skin, over which its final branches spread themselves; so that if two objects touch the skin at two different points within this area, they feel like one. In order to be felt as two separate contacts, they must be placed one on one special nerve-surface, and one on another. The size of the special spaces allotted to each nerve-unit is very different in different parts of the body. The determination of the size of these areas, and, by consequence, the accuracy of the sense of touch in various parts of the body, was effected by Weber. His method was at once so ingenious and so simple, that it is curious it should not have been adopted before. He took a pair of compasses, and having placed upon their points very small globules of sealing-wax, opened them to a small distance, and applied them to the surface of the body where the sense of touch was to be tested. The impression produced was as of a single point. He then opened them more and more until two distinct impressions were felt; and then measured the distance on a scale of inches and lines. He thus arrived at very definite and very interesting results. Among many other measurements of the least distances at which two points could be distinctly felt, we quote the following:

in. lines

in. lines

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The reader may verify these estimates for himself, but it is better to try them on some other person, because the impressions produced upon the eye and the mind by the sight and knowledge of the open compasses, have a tendency to bias the information received from the sense alone. The legs of the compasses must be applied both at the same instant, and not moved before the estimate is given. If they are moved, very different results will be given. From these statistics it will be seen that the tip of the tongue is the most discriminating part of the whole body. An easy verification of this will occur to every one when they remember how small a flaw in the teeth the tongue can detect-s flaw which is quite unnoticed by the tip of the finger, if that be applied to it. At first thought, it may seem strange that such acuteness of touch should be bestowed on an organ which is

rarely used to gain tactile information, and so placed as to be difficult of application to external objects; but when we consider how needful it is that the tongue should be able to feel every particle of food, so that we may know whether it is hard or soft, large or small, and be able to place it accurately between the teeth if it be not soft enough or too small, we cease to think the arrangement strange. The tongue, too, works in the dark with very little assistance from other senses, and so must be always on the alert.

Next to the tongue come the tips of the fingers and thumb. These are the salient points of that wonderful piece of mechanism, the hand. The hand of man is pre-eminently the tactile organ, and the free sweep of the arm, which enables it to turn in every direction, and to be applied to every part of the person, is an admirable accessory to its acute sense of touch. The lips are but little inferior to the fingers in acuteness of touch. A story is told of a blind girl, whose employment caused a thickening of the cuticle of her fingers to such an extent as to create a difficulty in reading her New Testament in raised letters for the blind. She at first tried the unfortunate expedient of paring the skin of her fingers, which made them more acute for a short period, but in the end, of course, duller, so that she could no longer read the loved volume. With a sentiment of grief and despair she stooped to give the sacred text a farewell kiss, and so discovered a new mode of studying it. Though, doubtless, this has become quite a platform story, it has in it so much physiological truth that there need be no hesitation in repeating it. Referring again to the probable theory that there is a separate area to each nerve-unit, it will be seen that that area occupies a space of six or seven square inches on the middle of the back or thigh, and only one square line on the tip of the finger. The former measurement is approximately 1,000 times as large as the latter. It is curious how nicely the discriminating sense of touch is adjusted to those parts where it is most likely to be of service. Thus, since the angles of the body are more likely to come in contact with other bodies than its depressions or the middle parts of its segments, we find the skin over the junction of two long bones more able to discriminate than that over their middle portion. The convexities of the joints are usually more discriminating than the concavities; the shoulder more than the arm-pit, and the elbow than the inside of its joint. Yet when we arrive at the hand the reverse is the case, for the palmar surface is more discriminating than the back part. This is for the obvious reason that we usually avoid knocking our knuckles against anything, while to grasp is so natural to the hand that it is quite an instinctive action, as every infant manifests.

A multitude of other points of interest might be dwelt upon did space permit. Thus, sensitiveness to tickling, and the improved appreciation of objects by moving the skin over them, would lead us into considerations quite different from those conrected with simple touch.

The sense of heat and cold is different from that of simple touch; and sensitiveness to these has no relation to the cognisance of tactile sensations. If with a cold finger you touch your brow, though the finger will feel any roughness on the brow far sooner than the converse, yet the brow feels the finger cold far more distinctly than the finger feels it to be warm.

the skin which overlies those muscles. These nerves, too, are quite capable of conveying definite information to the brain, without the assistance of the nerves of touch. The naked arm (in the dark) may be passed through the air where it touches nothing, and yet the range of its sweep, the position to which it is brought, and the amount of effort required to do all this, is known to the mind. In some rare instances this sense is lost without any of the others being impaired, and a case is on record of a mother who could hold her child while she looked at it, but directly she looked away she let it fall, because the muscular sense (not the muscular power) was gone.

Having indicated the distinction between the muscular and tactile senses, we must leave the reader to follow out for himself the complicated applications of these combined senses to gain a knowledge of outward objects. How, for instance, both are necessary to distinguish india-rubber from clay or from marble; and how the ideas of length, extent, and solidity are gained by passing the hand in one, two, or many directions over the outside of bodies. Let him also notice the wonderful adaptation of the human hand to obtain all this information. If he will take the trouble to do this, he will be struck with the marvellous complexity of the ideas which come trooping into the mind when so simple an action is performed as the grasping an object with the hand.

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6. Se plaire [4, ir.; see § 62], to take pleasure, to delight in anything, to like to be in a place, takes à before its object. Je me plais à la campagne, Je me plais à étudier, à lire,

I like to be in the country.

I take pleasure in studying, in reading.

7. Se dépêcher, se hâter, to make haste, take de before their object.

Dépêchez-vous de finir vos leçons,
Pourquoi ne vous dépêchez-vous
pas ?
RÉSUMÉ OF

d'hui ?

We pass on to notice briefly some yet more important applications of the sense of touch; and in order to do this it must be explained that the means by which we distinguish between hard and soft, rough and smooth, elastic and non-elastic, sticky and slippery bodies, by which also we gain our ideas of the form, size, distance, and situation of bodies, involves other sensations than those of simple touch. These ideas lie at the foundation of all mathematical science which treats of time and space. They are derived from the joint senses of touch, and of what has Le marchand s'en va-t-il aujourbeen called the "muscular sense." Simple pressure produces a sensation, as when a body is placed on the palm of the hand while its back rests on a table, but if we remove the table, or the hand, from it, a further sense of weight is conveyed to the mind. This idea of weight is derived from the knowledge the mind has that the muscles which hold the hand up are being exerted. So if the tip of the finger be passed along the edge of the table, it creates not only a consciousness of a number of successive contacts, but also a consciousness that the muscles of the arm and hand are exerted, and their position and condition is being continually altered. Now the nerves which run from the muscles to the brain are quite distinct from those which run from

Nous nous en allons demain.
Je m'en vais quand je suis fatigué.
Pourquoi vous fachez-vous contre

lui ?

Il se plait à jouer, il n'étudie ja.

mais.

Vous plaisez-vous chez vos parents?
Nous nous réjouissons de votre

De quoi vous réjouissez-vous ?

succès.

Nous nous en réjouissons.
Pourquoi vous dépêchez-vous ?

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1. Vous en allez-vous bientôt ? 2. Je m'en vais la semaine prochaine. 3. Pourquoi vous en allez-vous ? 4. Parceque jo ne me plais pas ici. 5. Vous plaisez-vous mieux chez votre tante qu'ici? 6. Je m'y plais mieux. 7. N'avez-vous pas tort de vous en aller si tôt ? 8. J'ai raison de m'en aller. 9. Ne vous

réjouissez-vous pas des malheurs d'autrui ? 10. Nous ne nous en réjouissons point. 11. Cet homme se fâche-t-il contre le jardinier? 12. Il se fâche contre lui parce qu'il ne veut pas so dépêcher. 13. Se fâche-t-il bien souvent? 14. Il se fache à tout moment, il se fâche d'un rien. 15. Ne vous dépêchez-vous jamais? 16. Je me dépêche toujours quand j'ai quelque chose à faire. 17. Ne vous plaisez-vous pas à courir et à jouer? 18. Je me plais à jouer et mon frère se plait à lire. 19. Vous réjouissez-vous de l'arrivée de l'ambassadeur ture? 20. Jo m'en réjouis. 21. Ne vous plaisez-vous pas en Amérique? 22. Je m'y plais beaucoup mieux qu'en France. 23. Votre écolier ne se plait-il pas chez vous ? 24. Il se plait chez moi, mais il désire retourner chez son père. 25. Dépêchez-vous, il est déjà

midi.

EXERCISE 74.

17.

1. At what hour does your friend go away? 2. He goes away every morning at nine o'clock. 3. Do you go away with him ? 4. I go away with him when I have time. 5. Will you make haste to finish your letter? 6. I make haste to finish it. 7. Does the gardener get angry with his brother? 8. He gets angry with (contre) him when he does not make haste. 9. Make haste, my friend, it is ten o'clock. 10. Why do you not make haste ? 11. I like to play, but I do not like to study. 12. Do you like to stay at my house? 13. I like to stay there. 14. Are you pleased at the arrival of your mother? 15. I rejoice at it. 16. Is not your brother wrong to go away so soon? He is right to go away, he has much to do at home. 18. Do you rejoice at other people's misfortunes? 19. I do not rejoice at them. 20. I rejoice at your success. 21. Does not your brother draw near the fire? 22. He goes from the fire, he is too warm. 23. Does that young lady get angry with you? 24. She gets angry at trifles (de rien). 25. Do you like to be in Paris ? 26. I like to be there. 27. Can you do without me to-day? 28. We cannot do without you; make haste to finish your work. 29. Do you want your penknife? 30. I want to use it. 31. Make haste to rise, it is six o'clock. 32. Is it fine weather? 33. No, Sir, it rains. 34. Is your father well this morning? 35. Yes, Sir, he is very well.

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Vos neveux nous ont parlé.
Nous avons parlé à votre père.
Le tailleur a-t-il fait mon habit?

Le boulanger a mis son chapeau,
Le cordonnier a ôté ses souliers.

Votre frère a dit quelque chose.
Votre sœur qu'a-t-elle dit?
N'avez-vous rien dit à mon cousin?
Je ne lui ai rien dit.

Je ne l'ai jamais rencontré.
Je ne leur ai jamais parlé.
Qu'avez-vous fait aujourd'hui ?
Hier nous n'avons pas travaillé.

Leur en avez-vous souvent parlé ?

Je leur en ai souvent parlé,
Je ne le leur ai pas encore dit.
N'avez-vous pas assez écrit ?

Il m'a écrit, il y a longtemps.
Il nous a répondu il y a un mois.

Avocat, m., barrister.
Cela, ceci, that, this.
Dit, from dire, said.
Etudi-er, 1, to study.
Gant, m., glove.

Your nephew spoke to us.
We spoke to your father.
Has the tailor made my coat?
The baker has put on his hat.
The shoemaker has taken his shoes off.
Your brother said something.
What did your sister say?

Have you told my cousin nothing?
I have told him nothing.

I have never met him.
I never spoke to them.
What have you done to-day?
We did not work yesterday.
Have you often spoken to them about

it?

I have often spoken to them about it,
I have not yet said anything to them
about it.

Have you not written enough!
He wrote to me a long time ago.
He replied to us a month ago.
VOCABULARY.
Garçon, m., boy.
Hier, yesterday.
Journée, f., day.
Lu, from lire, read.
Ministre, m., minister.

EXERCISE 75.

Mis, from mettre, putos.
Plant-er, 1, to plant.
Poirier, m., pear-tree.
Soulier, m., shoe.
Vu, from voir, seen.

2. L'avocat me l'a dit. 3. Lti 1. Qui vous a dit cela? avez-vous parlé de cette affaire ? 4. Je ne lui en ai pas encore 6. Je l'ai vu il y a parlé. 5. L'avez-vous vu dernièrement? 8. Nous avons quelques jours. 7. N'avez-vous pas écrit hier? lu et écrit toute la journée. [Sect. XXV. 9.] 9. N'avez-vous pas ôté vos gants et vos souliers ? 10. Je n'ai pas ôté mes 11. Le tailleur n'a-t-il pas gants, mais j'ai ôté mon chapeau. mis son chapeau? 12. Oui, Monsieur, il a mis son chapeau. 14. Je ne lui ai rien 13. Qu'avez-vous fait à ce petit garçon ? fait. 15. Ne lui avez-vous point dit que je suis ici? 16. Je ne le lui ai pas encore dit. 17. Qu'avez-vous étudié ce matin? 18. Nous avons étudié nos leçons et nous avons lu nos livres. 19. Le jardinier du ministre a-t-il planté le poirier ? 20. Ill's in-planté il y a plus de huit jours. 21. Avez-vous acheté un habit de drap noir? 22. J'en ai acheté un. 23. L'avez-vous porté aujourd'hui ? 24. Je ne l'ai pas encore porté.

SECTION XL.-THE PAST INDEFINITE [§ 121]. 1. The past indefinite is composed of the present of the dicative of one of the auxiliary verbs, avoir and être [§ 45 (8)], and the participle past of a verb. See the different paradigms of verbs, § 47, and following sections. J'ai parlé; je suis arrivé,

I have spoken; I have arrived.

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mis nos souliers et nos bas ce matin.

EXERCISE 76.

25. Nous avons

1. Have you studied to-day? 2. We have no time to study, we have read a page. 3. Have you not written to my brother? 4. I have not yet written to him. 5. Has not the German written to my mother? 6. He has not yet written to her. 7. Have you told () my mother that I have taken (pris) this. book? 8. I have not yet seen your mother. 9. What have you done this morning? 10. We have done nothing. 11. Have you taken off your coat? 12. I have not taken off my coat, it is too cold. 13. Has the bookseller written to your brother? 14. He wrote to him a long time ago. 15. Did he write to him a month ago 16. He wrote to him more than a year ago. 17. Have you planted a pear-tree? 18. We have planted several.

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19. Is it too cold to (pour) plant trees? 20. It is too warm. 21. What has the gardener done to your little boy? 22. He has done nothing to him. 23. Has any one done anything to him? 24. No one has done anything to him. 25. Is anything

the matter with him? 26. Nothing is the matter with him, 27. Has your father put on his black hat? 28. No, Sir, he has not put on his black hat. 29. What has your brother said? 30. He has said nothing.

Ezekid, sq3 BC

COPY-SLIP NO. 85.-EZEKIEL, 595 B.C.

France in Europe

COPY-SLIP No. 86.-FRANCE IN EUROPE.

Great Britain and Ireland.

COPY-SLIP NO. 87.-GREAT BRITAIN AND IRELAND.

Hareld was killed at Hastings 1066.

COPY-SLIP NO. 88.-HAROLD WAS KILLED AT HASTINGS, 1066.

Ionian Islands ceded to Greece in 1865.

COPY-SLIP NO. 89.-IONIAN ISLANDS CEDED TO GREECE IN 1865.

fedde, or Yedda, the capital of Japan

COPY-SLIP NO. 90.-JEDDO, or yeddo, THE CAPITAL OF JAPAN.

LESSONS IN PENMANSHIP.-XXIII. THE Copy-slips that accompany this lesson contain two examples of a kind of writing that we have not yet brought under the notice of our readers. Hitherto the turns of the letters in our copy-slips, both at top and bottom, have been curved; but in Copy-slips Nos. 89 and 90 it will be noticed that the turns of the letters are angular or pointed. For this reason this elegant style of writing is called "Angular Hand." It is also called "Ladies' Hand," because this pointed kind of writing is commonly adopted by ladies, and taught in ladies' schools; while in the handwriting of men, for the most part, the letters are

more rounded in the manner exhibited in Copy-slip No. 88. Roundness on the one hand, and angularity on the other, will be found to be the most essential marks of difference in the writing of men and that of women; the former being also distinguished by the neatness and compactness of the letters and the shortness of their loops and tails, while the latter is usually larger and spreads over much space, while the tails and loops of the letters are long and straggling. It must be remembered that in pointing out these as the chief points of difference in the handwriting of men and women, we are only speaking generally and directing attention to the more striking charac teristics of the different styles of writing usually adopted by

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