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gambia and the Niger, less the Senegal Protectorate, which was restored to Senegal. At the same time the military territories were broken up and became a part of the colony. The first military territory was incorporated in Upper Senegal-Niger, and is administered by a colonel under the authority of the military governor; the second territory was handed over to the civil administration and the third is still an autonomous unit. Upper Senegal-Niger is entirely under civil administration, with the same judicial and educational systems as the other colonies comprised in the governmentgeneral. The budget of the colony for 1916 amounted to $1,788,641; the local budget for 1914 was $1,918,981. The most important and populous towns are Bobo-Dioulasso (8,736 inhabitants), Bamako, the capital (6,553), Sikesso (7,544), Segou (6,550), Kayes (5,900). All the principal towns have urban schools. There is a professional school at Kayes and a school for sons of chiefs. There is a Mussulman superior school at Timbuktu (5,100 inhabitants), which has 67 pupils. The natives cultivate ground nuts, maize, millet, cotton and rice; rubber and kariti are also produced. The principal native industries are pottery, jewelry, brick and leather-making and weaving. Cottons, foodstuffs and metal work form the chief items of import, while cattle, ground nuts, hides, wool and rubber are exported. In 1912 there were 4,050 miles of telegraph line and 74 miles of telephone line. The Senegal-Niger Railway extends from Kayes to Koulikoro, a distance of 349 miles. Small steamboats ply between Koulikoro and Timbuktu. In 1914 the imports into Upper Senegal were valued at $1,079,426, and the exports amounted only to $462,164. The Niger (territory) is farther inland than Upper Senegal, therefore, more remote from the seaports through which all West African trade must pass; in consequence the over-seas trade is inconsiderable. The value of the imports into the Niger in 1914 amounted to $193,117, the principal articles, in addition to government purchases, being cotton goods and tobacco; the exports reached $117,656 in the same year and consisted mainly of cattle, hides, ostrich feathers, native salt and tanned sheep and goat skins. Consult Lenfant, 'Le Niger (Paris 1903); id., 'La grande route du Chad' (ib. 1904).

SENEGAMBIA, sen-ě-găm'bi-a, West Africa, so named from the Senegal and Gambia rivers (qq.v.), an extensive region comprising the countries between lat. 10° and 17° N.; long. 4° and 17° 30′ W.; bounded on the north by the Sahara, south by Guinea and west by the Atlantic. The area is estimated at from 400,000 to 700,000 square miles, and is almost wholly under French influence, with the exception of Bissagos Island and some coast territory at the mouth of the Rio Grande River, belonging to Portugal, and the British Gambia colony at the mouth of the Gambia. The name Senegambia is not used by the French, who call their colony and protectorate Senegal (q.v.). The western portion of the country is a low, flat and, to a great extent, swampy plain. East of this the country is mountainous, and the valleys run north and south. The principal rivers are the Senegal, the Gambia, the Jeba or Rio Grande and the Nuñez. In the level tract bor

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dering the coast the rivers during floods overflow their banks, inundating the plains, and become connected with one another by means of canals. On the lower Senegal, so far as the inundation reaches, vegetation is very luxuriant. Rice, maize and other grains, with bananas, manioc and yams, are cultivated equally on the hills and plains. The orange, citron and other fruits introduced by the Portuguese are now extensively cultivated on the hills. Wild animals comprise the elephant, hippopotamus, monkey, antelope, gazelle, lion, panther, leopard, hyena, jackal, crocodile, etc. The climate is intensely hot and unhealthful for Europeans. The inhabitants are of many races, the principal being the Yolofs, Foolahs and Mandingoes. These negro tribes inhabit for the most part Middle Senegambia, between the Senegal and the Gambia. Upper Senegambia, to the north of the Senegal, is largely inhabited by Moors, who carry on an extensive trade in gum, etc., with the Europeans. The total population is estimated at 12,000,000.

SENEY, sẽ'ni, George Ingraham, American banker: b. Astoria, Long Island, N. Y., 12 May 1826; d. New York, 7 April 1893. He was educated at the Wesleyan University and at the University of the City of New York where he was graduated in 1847. He engaged in the banking business and in 1877-84 was president of the Metropolitan Bank, New York. He lost heavily at the time of the bank's failure in 1884, but later succeeded in partially re-establishing himself financially. Before 1884 his benefactions amounted to about $2,000,000. He gave $500,000 to establish the Seney Hospital in Brooklyn and $500,000 to both the Wesleyan University and the Methodist Orphan Asylum in Brooklyn. He aiso gave $250,000 to Emory College and the Wesleyan Female College, Macon, Ga., and liberal sums to other public institutions. He sold his famous collection of paintings at auction in 1885, receiving $406,910 for them. From a later collection he gave 20 valuable paintings to the Metropolitan Museum of Art, New York.

SENIJEXTEE. See SALISHAN INDIANS. SENILE DISEASES. See OLD AGE and ITS DISEASES.

SENILITY. To obtain a clear conception of senility we must consider old age as consisting of two periods, the presenile and the senile. Physiologically these periods exist and are divided by a critical period called the senile climacteric which occurs about the 70th year. This period corresponds to puberty during the period of development and the menopause and the male climacteric during the period of maturity. The senile climacteric, like the male climacteric, usually causes so little distress that it passes unnoticed. Occasionally those around the aged person notice marked changes in mentality, more profound physical changes, greater debility, while some prominent manifestations of senility will appear less pronounced. In some cases the climacteric changes are very evident and the person passes rapidly from a condition of bright middle-aged mental and physical activity into a state of senile decrepitude.

During the senile climacteric the organs and tissues which have degenerated slowly now

break down rapidly and the degenerative processes which have gone on rapidly before become less active. There is really a readjustment in the degenerative processes and this is followed by the progressive degeneration of all the organs and tissues and a diminution in their functions.

The toute ensemble of senility is characteristic. The stature is diminished through the greater curvature of the spinal column, flattening of the pelvis, depression of the heads of the femurs and, generally, broken-down arches. A further apparent diminution in stature is occasioned by the attitude of aged persons. The head sinks down and forward, the knees are bent to maintain equilibrium and there is a general slouching appearance which is partly relieved when a cane is used. The skin becomes pale and thin and, owing to the waste of subcutaneous fat and muscle, it becomes flabby, wrinkled and falls into folds. The teeth fall out, the alveolar process in which the teeth are imbedded wastes and there is a waste of the bone substance of the lower jaw. When the jaws are now closed the lower jaw is drawn further up to meet the upper jaw and the small, weazened face of the aged is produced. The eyes become dull and there is generally a gray ring called the arcus senilis around the iris. The nose and ears become thin and pale, the lips become flaccid and darker in hue, the color being a fair indication of the extent of the blood impairment. The hair rapidly whitens or falls out but there is often a growth of hair in unusual places as in the ears, nose, chin and on the upper lip of women, etc.

The face is expressionless and it is seldom roused to reflect interest or emotion.

The mental changes in senility are peculiar. In those who have had little intelligence or education there is a gradual diminution in all mental faculties. Memory fails until the event of a moment ago is forgotten, reason and judgment are lost, interest can be aroused with difficulty and only with greater difficulty can it be maintained; only the most powerful sensory impressions are received, interpreted and get responses. The emotions are dulled, there is neither fear nor hope, joy nor sorrow, and the individual will smile or weep without apparent cause. Usually he is apathetic, gradually lapsing into a state of complete amentia in which even the fundamental instinct of selfpreservation is lost.

The intelligent, educated person generally retains reason and judgment but the mind is less active and brain fag develops rapidly. Memory is impaired, recollections of early events coming unbidden while later events cannot be recalled by any effort of the will. Old persons find it difficult to displace old ideas, habits and hobbies by new ones, and they are, therefore, called old-fashioned. Imagination

sometimes develops delusions, such delusions always possessing the element of self-aggrandizement. It is difficult to arouse interest or maintain attention. Under some extraordinary stimulus mental acuity will be revived but this lasts only a short time and is followed by mental exhaustion. Weak sensations are not received owing to the impairment of the sensory organs but the mind correctly interprets sensations that it does receive. The emotions

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are dulled, there is seldom hope or joy, but usually there is a depressed, hopeless resignation to the inevitable. Sometimes religious teachings overcome the haunting fear of death, in some cases a materialistic philosophy makes the mind indifferent to death. Usually as the mind becomes weaker the fear of death and all other fears diminish; it is doubtful, however, if there is developed an instinct for death as Metchnikoff assumed.

Some individuals possess remarkable mental powers in old age. A critical study of the mentality of such individuals reveals in almost every case a concentration of mental faculties in one channel or direction while in every other direction there is profound mental impairment. The absent-mindedness and other peculiarities of these aged geniuses are really evidences of mental impairment. In the rare cases where the mental faculties retain their power with little or no impairment, the physical changes are slight and the whole process of senile involution is apparently retarded.

A remarkable phenomenon in senility is the approximation of the sexes toward a neuter type. The female chest gradually approaches the senile male chest in shape and the male pelvis becomes flattened until it resembles the female pelvis. In the male the hair on the face becomes thin while there is a growth of hair on the face of the female. His voice becomes higher, her voice becomes lower in pitch. The small weazened face and the dull expression give to both a similarity in features. It is a common observation that old couples resemble each other and through long association they exhibit similar mental traits. This phase of senility has not been sufficiently studied. While imagination undoubtedly plays a part in noting this resemblance it is in many cases sufficiently marked to attract attention. Virilescence usually begins soon after the menopause; its counterpart in the male is rarely observed before the period of senility. See OLD AGE,

I. L. NASCHER, M.D., Author of Diseases of Old Age and Their Treatment.

SENIOR, se'nyor, Nassau William, English political economist: b. Compton, 26 Sept. 1790; d. Kensington Gore, London, 4 June 1864. He was graduated from Eton and from Oxford, and in 1819 was called to the bar at Lincoln's Inn. He was the first professor of political economy at Oxford 1825-30; was appointed a master in chancery in 1836 and resumed his chair at Oxford in 1847. Of his writings, which comprise a number of excellent treatises on political economy, mention may be made of An Outline of the Science of Political Economy' (1836); 'Political Economy (1850); Essays on Fiction (1864); and Historical and Philosophical Essays' (2 vols., 1865).

SENLAC, sĕn'lăk, or HASTINGS, Battle of, the one battle in the Norman conquest of England. It was fought 14 Oct. 1066 at Senlac Hill, a few miles from Hastings, between William, Duke of Normandy, and Harold II (q.v.), king of England. Harold's fortified position was attacked at 9 A.M. by the Norman army in three divisions, strong in cavalry and archers, the centre led by William in person. The English made a stout resistance with their battle

axes and other weapons, but part of them pursuing William's flying Bretons, the whole body was led into a trap by the feigned retreat of many of the Norman forces, the disordered ranks of the English being easily overborne by their enemies, who stormed and carried the hill. The death of Harold, who was pierced in the eye by an arrow about sunset, disheartened his men and they shortly dispersed. Battle Abbey was erected by William on the field where Harold fell and portions of it still exist. Among the literary treatments of the event are two poems of Chatterton and a drama by Cumberland. Consult Green, The Conquest of England' (1899); Freeman, Norman Conquest' (Vol. III, 1876). See WILLIAM I.

SENN, Nicholas, American surgeon: b. Buchs, Switzerland, 31 Oct. 1844; d. Chicago, Ill., 2 Jan. 1908. He was brought to this country when a boy and settled in Wisconsin. He was educated at the Chicago Medical College and the University of Munich, was house physician at the Cook County Hospital 1868-69 and practised medicine in Wisconsin 1869-93, being at one time surgeon-general of that State. After 1893 he practised in Chicago, where he was attending surgeon of the Presbyterian Hospital and surgeon-in-chief of the Saint Joseph's Hospital. He was appointed in 1898 chief surgeon of the Sixth army corps, ranking as lieutenant-colonel of volunteers and chief of staff in the field. From 1884-90 he was professor of surgery at the College of Physicians and Surgeons, Chicago, and after 1890 professor of practical and clinical surgery at the Rush Medical College. He was also professor of surgery at the Chicago Polyclinic and lecturer on military surgery at Chicago University. Among his works are 'Four Months Among the Surgeons of Europe'; 'Experimental Surgery' (1889); Surgical Bacteriology) (1889); Principles of Surgery'; 'Tuberculosis of Bones and Joints; Medico-Surgical Aspects of the Spanish-American War'; and a Nurse's Guide for the Operating Room (1903).

SENNA, Nelson Coelho de, Brazilian lawyer and author: b. Serro, Minas Geraes, 11 Oct. 1876. He was educated at the Normal School at Diamantina, Historical Institute at Rio de Janeiro, São Paulo, Nichtheroy and Ceará, and the Academy of Juridical Sciences, Ouro Preto. He has been successively secretary of the police and agriculture departments of his native state, professor of Brazilian and history at Mineiro Gymnasium, Bello Horizonte, and vice-president of the council of public instruction of Minas Geraes. He served in the first, second and third Latin-American scientific congresses. He is member of many learned societies both of South America and of Europe. His published works are Questões internacionães do Brazil'; ‘A Edade da Pedra do Brazil'; 'Elogio literario de José Eloy Ottoni, poeta sacro brasiliero'; A Hulha Branca'; 'Los Indios del Brazil'; 'Contes Sertanejos'; 'Paginas de historia religiosa do Brazil'; 'Discursos Academicos; A Bacia do Rio Doce,' etc. edited Annuario Historico e Estatistico do Estado de Minas Geraes after 1906.

Не

SENNA, a nauseous, bitter but valuable purgative drug, obtained from the leaves of several tropical species of the leguminous genus Cassia (q.v.), The officinal species are shrubby

plants, with nearly regular, five-parted flowers in racemes and alternate, pinnate leaves subdivided into many leaflets. Alexandrian senna is formed of the leaflets of Cassia acutifolia, which are dried by cutting the shrubs until the leaflets shrivel and tumble off. C. angustifolia grows in and about Arabia, where it was used in domestic practice by the Arabs, who were apparently the first to introduce the drug to Europe. It is called Indian senna, as it is cultivated in South India. Bombay senna is a very inferior quality of this variety, much mixed with stalks and dead leaves; the variety Tinnevelly, on the contrary, is the largest and cleanest senna in commerce. C. obovata, formerly of good repute, producing senna-pods and cultivated in India, is now classed among the inferior qualities and rarely met with except as an adulterant. Still other sennas are known under the name of the port of export, or place of growth. American or wild senna is the Cassia marylandica, a perennial abundant in the southern United States, sometimes eight feet high, with obtuse, oblong leaflets, numerous yellow flowers, with clawed petals and long linear pods. It has the qualities of Oriental senna in a lesser degree and was formerly used for the Bladder same purposes in popular medicine. senna is the Colutea arborescens and is also a purgative sometimes called bastard senna.

SENNAAR, să-när', Anglo-Egyptian Sudan, a province extending between the Blue and the White Nile, from Khartum to Fazogl. It covers an area of 40,000 square miles. Generally speaking, it is a broad plain with occasional granite mountain heights and is at the north steppes thickly overgrown by wild grass and bushes; the southeast has tall forests intersected by fertile valleys. Gold and iron occur, and palms, tamarinds, etc., grow on the plain. Monkeys, lions, gazelles, giraffes, elephants, besides marsh and water-birds, are numerous; also domestic animals. The chief occupation is fishing. The products are rice, grain, melons, tobacco, sugar, senna, ebony and sandal-wood. The climate is exceedingly warm and during the rainy season is unhealthful. The inhabitants are negroes - the Funj, Nubian and Galla, and of mixed races, and are sometimes classified according to color. Slaves are imported. Sennaar (pop. 18,000), the former capital, stands on the Bahrel-Azrik or Blue Nile. The other towns are Fazogl (or Famaka), Roséres, WodMedineh and Khartum. Near the latter town are the extensive ruins of Soda, the ancient capital of the Funj, a negro race, who migrated there from Central Africa in 1500 and founded the Senaar kingdom, which lasted until 1821.

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SENNACHERIB, se-nǎk'ë-rib, an Assyrian king, son of Sargon, succeeded his father on the throne 705 B.C. Among his first acts as king was the suppression of the revolt of Babylonia and after accomplishing this he directed his arms against the Aramean tribes on the Tigris and Euphrates, of whom he took 200,000 captive. He then reduced a portion of Media, till then independent; placed under tribute Tyre, Aradus and other Phoenician cities; advanced against Philistia, made war upon Egypt and finally marched against Hezekiah, king of Judah, who had revolted. Hezekiah, terrified, yielded in a panic, and paid the tribute exacted, namely, 300 talents of silver and 30 talents of

gold On his return to Assyria Sennacherib made another attack on Babylonia and afterward reinvaded Judah. Having marched through Palestine he laid siege to Libnah and Lachish and finding that his messengers Tartan, Rabsaris and Rabshakeh had failed in obtaining the submission of Hezekiah, he wrote an intimidating letter to Hezekiah; but before he could bring his forces against the city, according to the Bible record, a visitation from the Lord during the night caused the death of 185,000 of his troops. In consequence of this calamity Sennacherib returned to Nineveh and troubled Judah no more. From Herodotus we learn of the Egyptian tradition regarding the destruction of Sennacherib's host, which is, that a multitude of field mice devoured all the quivers and bowstrings of the enemy and gnawed the thongs by which they bound on their shields. No mention of the destruction of his host is found in the monuments of Sennacherib. This ruler was one of the greatest of the Assyrian kings and was not only a great warrior but also a great builder. His largest architectural work was the palace of Koyunjik, which covered an area of fully eight acres. Of the death of Sennacherib all that is known is contained in the brief Scripture statement of 2 Kings xix, 37 and Isa. xxxvii, 38, from which it appears he was murdered by his own sons. See ASSYRIA; ASSYRIOLOGY; BABYLONIA.

Bibliography. Johns, C. W. H., History of Assyria' (London 1911); King, L. W., Sennacherib and the Ionians' in Journal of Hellenic Studies, Vol. XXX (London 1910); Olmstead, A. T., Western Asia in the Reign of Sennacherib' in American Historical Association, Annual Report (Washington 1911); Rogers, R. W., History of Babylonia and Assyria (New York 1900); id., Cuneiform Parallels to the Old Testament' (New York 1912); Schrader, E., 'The Cuneiform Inscriptions and the Old Testament) (I, 278-310); Smith, G., The History of Sennacherib' (London 1878); Tiele, 'Babylonisch-Assyrische

Geschichte (Gotha 1885).

SEÑORA AMA, drama in three acts by Jacinto Benavente, was acted at Madrid 22 Feb. 1908. The story is one of peasant life on the plains of High Castile, a presentation of contemporary rural Spain as brilliant in color, but sordid and dead within, palsied with the degeneracy of a decaying civilization, from which all impetus and inspiration have disappeared, and merely husks of Church and State remain. Few dramas are of equal pessimistic power. As a veracious psychologic study, the play is of great value, depicting the sterility of the retarded country-side which is sunk in jealousies, sensuality and greed, where only the maternal instinct breathes unstunted amid the insentient fields. The minutest details are of unimpeachable realistic veracity. The author avoids any semblance of generalization. Yet in the absence of physical descriptions, the aspect of the Castilian plain and sierra is projected from the austere mentality of the peasantry with a rudeness of coloring and distinctness of outline which the Spanish painters have not surpassed. The sense of the motionless background provided by centuries of Spanish civilization is conveyed with the same economy of means. Upon the technical side the play is one for the artist. In illuminative insight and

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potency of imaginative suggestion, although a work of pure realism, it rivals in completeness the universality of idealistic art. There is the customary lack of coups de théâtre, reinforced by a contemptuous disregard of the conventional conceptions of the stage. The first edition appeared at Madrid, 1908. Consult also Benavente, Teatro' (Vol. XVII, Madrid 1909). The English translation is included in the third series of the 'Plays by Jacinto Benavente' (New York 1917 et seq.).

JOHN GARRETT UNDERHILL.

SENS, France, archiepiscopal city and capital of an arrondissement in the department of Yonne, situated on the right bank of the Yonne River, 70 miles southeast of Paris. The city contains the cathedral of Saint Etienne dating from the 12th century and a fine city hall, which contains also a museum of precious stones, a library and an art gallery. Manufactures consist chiefly of fertilizers, farm implements, leather, glue, serge, etc., and there is considerable trade in wine, corn, hemp and flax. Sens was known in ancient times as Agenticum and later as Senones and was one of the largest cities of Gaul, vestiges of the old Roman walls still being visible. Pop. about 15,000.

SENSATION. This term is used broadly to designate any form of consciousness which originates immediately from the stimulation of the sensory end-organs of the nervous system (e.g., the eye or ear). This usage fails, however, to distinguish between sensation and sense perception. In the narrower psychological meaning sensation applies to the elementary forms of consciousness originating under the conditions mentioned. Sensations are in this technical sense cognizant of simple sensuous data, such as colors, tones, etc., whereas perceptions are cognizant of objects. For example, we perceive a sunset, a complex visual object displaying various color qualities, e.g., whiteness, redness, etc., of which we become conscious as sensations. These sensations are regarded as simple and incapable of further analysis. We perceive a musical sound when a note is struck upon the piano. This sound is made up of a simple fundamental tone and its overtones. Our consciousness of one of these simple pure tones is a sensation. On these terms sensation is evidently largely an abstraction of the psychologist. Our actual sensory consciousness is commonly cognizant of objects, i.e., is perceptual.

Certain authors extend the meaning of sensation so as to include not only all elementary sense qualities arising directly from sensory stimuli, but also all such qualities when aroused in processes of imagination, as when, for instance, one closes the eyes and gets a visual image of a rose. They speak, therefore, of peripherally and centrally originated sensations. In so far as this usage calls attention to the fact that the sensory and ideational elements are qualitatively alike, whether called out by central or peripheral stimulation, it is justifiable. But well-established custom is violated by the procedure and it may be questioned whether it will endure.

The commonly recognized groups of sensations are as follows: color, including brightness, sound, taste, smell, pressure, heat, cold,

pain, articular, tendinous, muscular, thirst, hunger, sex, circulatory (including tickling, itching, etc.), respiratory and static (dizziness sensations from the semi-circular canals of the ear).

Psychologists are wont to treat sensation under four principal aspects, i.e., .quality, duration, intensity and extensity. Of these four quality is generally considered most basal. A sensation of tone, for example, may vary in duration without appreciable alteration of the pitch, which constitutes its most essential quality. Again, a color sensation may under certain conditions vary in extent without noticeable variation of quality. But a sensation which had no duration or no intensity would obviously be no sensation at all, and in general, if any aspect which a given sensation can manifest be reduced to zero, the whole sensation vanishes. Certain psychologists maintain that every sensation possesses all these aspects, but probably the majority hold that auditory sensations at least, and perhaps a few others, like smell, are lacking in extensity. Certain interesting facts concerning the relations of sensation intensities to one another are formulated in Weber's and Fechner's laws. (See WEBER'S LAW). According to Weber equal differences in sensation intensity are produced by relatively equal differences in stimulus intensity. If we place a weight of 20 grams upon the hand, we shall notice no change until we have added another whole gram, i.e., of the original stimulus. If we take a weight of 100 grams, we must now add not one gram but of 100 grams or 5 grams, before we notice a change. The same sort of relation holds for a number of the senses within the medium ranges of intensity.

Sensations depend upon the stimulation of specific end-organs connected with specific brain centres. No one ever gets visual experiences who does not possess an optical centre in the cerebral cortex and who has not at some time

possessed a functioning retina. No one ever gets auditory experience without a similar use of the ear and the auditory cortex and the same sort of thing is true for each of the sensations.

The stimuli which produce sensation are classified as adequate and inadequate, internal and external, mechanical and chemical. The only pair which requires any explanation is the first. Each sense organ is fitted to respond primarily to some special form of physical stimulus, e.g., the eye to light, the ear to sound, etc. Such stimuli are called adequate. In addition to these adequate stimuli, however, the senses can be aroused by other forms of stimulation designated inadequate. Thus an electric current conducted to the frontal region of the head may produce sensations of light. Pressure on the eyeballs similarly occasions color sensations. It may be added that sensations often continue after the stimulus is removed. Such sensations are known as after-sensations. In the case of vision they present very remarkable characteristics and are commonly called afterimages.

Sensations combined in various ways and reinstated in the form of memory and imagination furnish the basis of all our ideas. They are accordingly the foundations upon which rests the whole structure of knowledge. To understand their function in this particular it must be borne in mind that in actual experience they are not

mere naked qualities, but that they serve to convey meanings and that it is in this manner that they achieve fundamental import for mental life.

Bibliography.- James, Principles of Psychology) (New York 1890); Külpe, Outlines of Psychology (1895); Bain, 'Senses and Intellect (London 1855). For special senses see literature of special articles, VISION; ORGANIC SENSATIONS, etc.

JAMES ROWLAND ANGELL, President of Yale University, New Haven, Conn.

SENSATION, Organic. The term organic sensation is nowadays applied broadly to all those sensations which originate from internal bodily stimulations. They are called forth by mechanical, chemical and thermal changes in the organism. Among the sensations which are commonly held to belong to this group may be mentioned pain, pressure and temperature from the interior of the organism; sensations from the muscles, tendons and joints; sensations from the alimentary canal; sensations from the circulatory, respiratory and sexual organs; and finally sensations which are supposed to originate from the semi-circular canals of the internal ear. These sensations are sometimes distinguished from the other forms of sensation like vision and hearing on the ground that they convey to us primarily a knowledge of the state of our own organism rather than knowledge about the external world. This distinction is, however, only roughly accurate.

The sensation qualities which originate from these senses can be described only with approximate accuracy, for psychological analysis has not succeeded as yet in unraveling all their complexities. Pain, pressure and temperature are familiar experiences requiring no description. From the muscles we obtain sensations which suggest dull pressure, becoming under conditions of fatigue somewhat unpleasant and in condition of cramp leading to distinct pain. From the tendons we obtain sensations which inform us of the movement of our limbs and particularly sensations of strain and resistance. It is generally held that from the joints we receive important sensations which also inform us of the movements of our limbs and in particular make us aware of their position. Certain authorities have called in question - both on anatomical and psychological grounds - the significance of the articular sensations. These sensations from muscles, tendons and joints commonly occur together and are sometimes spoken of in a group as the "muscle sense" or the kinæsthetic senses. Experimental devices are necessary in order to isolate them from one another. The circulatory processes are probably responsible for such subjective sensations as feverishness, shivering, “pins and needles,” itching, tingling and tickling. Of course certain of these sensations are at times called forth by direct external causes. The heart itself occasionally gives rise to very distinct sensations, commonly of a painful character. The respiratory organs are probably responsible for our feelings of suffocation, of "stuffiness" and closeness as well as for those of freshness and stimulation in the air. The alimentary canal occasions at least three specific qualities: hunger, thirst and nausea. Undoubtedly the processes of secretion and excretion affect the general tone of consciousness from time to time,