was concerned with the question as to the fidelity and longevity of these special memories or types of memory, as related to each other, and with the discovery of laws according to which they might be revived. (See MNEMONICS). But with the introduction of the unconscious as a dynamic factor, the recalling of a previous experience is explained on a new principle. Memories are thus seen in the form of ideas to be reproduced into consciousness by virtue of forces which are mainly unconscious, and over which consciousness has only an indirect control, and the study of memory as such retires to an importance secondary to the study of the causes why some things tend to be remembered and others tend to be forgotten. This trend or tendency on the one hand to be forgotten or on the other to be remembered is now known to be determined by the unconscious wish, a force which is termed the libido and which is the prime mover, although uniformly unrecognized, of all the activities of the ego, both conscious and unconscious.

The mental mechanisms by which the unconscious pervades and indirectly controls all the conscious expressions, whether activities or thoughts, will be discussed under the title PSYCHOANALYSIS. In connection with memory it is necessary here only to point out that what we remember is only the residua after the work accomplished by the processes of repression, during which most of our former experiences are forgotten. On the fundamental principle that what is unpleasant in experience is from earliest infancy rejected by the individual ego, and regarded as if it did not exist, we may regard the ego as similarly rejecting or repressing the memories of impressions associated with the unpleasant or painful incidents. This explains why some things are forgotten and others are remembered. The unconscious, which functions solely on the principle of accepting or striving for the pleasurable and rejecting or repressing the painful, therefore furnishes the motive force for injecting certain ideas into consciousness, and restraining other ideas from entering. On this fact depends the further phenomenon that the dynamic factor called the libido, in becoming attached to certain ideas which are thrust out of consciousness, may be converted and its force applied to vegetative functions of the body producing in many cases certain forms of disease. See PSYCHOTHERAPY.

Memory, however, does not depend on repetition of stimulus alone. There are variations in intensity and duration of stimuli, modifications in plasticity of the nerve-cells themselves, the quality of attention, and above all the native individual character of health of the nerve-tissue itself all of which factors enter into the everyday variations in memory that are familiar to all. The fixity and enduring quality of the memories of childhood are proverbial, and are due to the great plasticity of the youthful nervecells, as well as to the intensity of the early pictures. That one person should have a good visual memory and a poor auditory memory, and vice-versa, must naturally be interpreted as due to variations in individual capacity. Modern pedagogy has slowly recognized these variations, and the greater prominence given to play, and to methods of precision, be they manual, lingual, auditorial or visual, and less to

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distinctly formal methods of memorizing as a purely visual process from a printed page, may be regarded as evidence of this wider recognition that memory should be a generalized function, and not a pedantic cramming of any sort. A well-trained muscular system may be of far greater use to a man than any of his acquired knowledge. It is impossible to train certain children to do certain things, whereas in other directions training may result in great proficiency.

Disorders of Memory. The classifications of disorders of memory into those of defect and those of excess is based on the old psychology which laid most of the defects to lesions in the cortex of the brain. The newer view, while admitting the loss of memory evinced by the physical defect in the brain or nerve substance, admits also a purely functional deficiency in various memories which is determined by the unconscious wish and is entirely independent of any organic lesion or defect. It is agreed by most psychologists that the native retentiveness in any given individual does not itself alter, although there may be in one individual a finer nerve and brain structure than in another, enabling one to perceive and therefore retain finer distinctions. But the ability to recall at will, which is the essential quality of a good memory in the ordinary sense, is dependent solely upon the proper alignment of the unconscious wish with the desires of the conscious life, which are determined by the social environment of the individual.

The general term for deficiency or loss of memory is amnesia, although this term fails to express the various distortions of memory, the illusions or slight absences; and there are no technical words to distinguish temporary or permanent, periodic or progressive stages of the amnesic process. Inasmuch as memory is not one thing, but a great assemblage of processes which reflect a vast variety of psychological functions, situated not in the brain alone, but almost anywhere in the nervous system, a "defect in memory," as defined by Jastrow, "is an expression of the incapacity of a group (or of certain groups) of centres to exercise their normal functions; or a tendency which they show to functionate in an abnormal manner.» Defects of memory may be general or special. General defects may be due to an incapacity on the part of nervous centres to establish residua. This type is found in those people who never remember what they see, and, notwithstanding frequent repetition of an aot, never acquire proficiency in it. Occasionally a reverse general condition is manifest wherein the power of memory is unduly exalted and impressions of past experience reappear with unusual brilliancy, Such states are known in fevers, in intoxications of various kinds as of alcohol, opium, etc., and in the hypnotic trance. Special defects may arise in which particular isolated experiences are cut out of the mind. Thus alcoholic amnesia, that may forget even a committed crime, is an illustration. Somnambulism and other hysterical states are characterized by defects of this special type. Another form of defect is observed when associated memorygroups are blotted out, as in the special disorder aphasia. (See APHASIA; SPEECH, DEFECTS OF). Memory may be falsely localized in time, or in order; imaginary additions to

real events may be present; or illusory remembrances of what has never been experienced occur. Disorders of memory are never primary conditions but depend upon either the physical nerve or brain defect for which there must always be a corresponding deficiency in memory or upon the psychological conditions referred to above, where the specific memories are inhibited by associations with unpleasant or painful situations. Through the technique of psychoanalysis a great amount of forgotten material can be restored to memory by means of living over again the situations in which occurred the events responsible for the apparent obliteration of the memory.

Psychologically considered, memory defects may occur either in the storing or retentive part of the nerve-cells, or they may involve the much more complicated and associated process of reproduction of the retained images. Both processes may be involved at the same time. In imbecility, idiocy, dementia, etc., a born or acquired loss of retentive power is present. In pianists-for example, Paderewski- or chessplayers Morphy, Pillsbury, etc., a state of localized hyperamnesia is present. This group would include all such prodigies. Occasionally one sees these two groups represented in one individual, as in an imbecile who has great power for mathematical calculation, etc. A case of this kind proves that the old assumption of closely localized memory-centres is false. Memory may be said to reside in all parts of the sensory nervous system. In another group the ordinary amnesias may be placed. These vary with each individual and depend largely on the healthy tone of the nervous system. A third group would include the paramnesias, or illusions of memory. In this condition (1) there is a loss of distinction between memory of things which really did happen and an imagination of things which never did or could. The so-called "constitutional liar is an example of this inability to distinguish between real and imaginary, and many types of insane persons are similarly affected in an extreme degree. The reverse of taking an imagination for a real thing is (2) taking a real thing experienced for the first time as a memory of something experienced before- thought of having seen, heard or felt "just that same thing before," also called "deja vue." Such a feeling has nothing to do with native retentiveness, but only with the "feeling of familiarity," which is essentially the presence of an organic sensation which is absent in the simple paramnesia. In some insanities this form of double memory is very prominent and leads to the belief on the part of the person so affected that he is prophesying when he is only recalling what he experienced before. (3) There is also an associated paramnesia in which things actually experienced suggest ideas falsely taken as memories of other things never experienced. This condition is seen in children and often leads to false testimony. It is also responsible for most "presentiments" or alleged antecedent knowledge of what has happened. Examples of such memories of the actually non-existent are seen in the stories of faith cures, where all the healing is that of ills that never really existed, save as associated false memories. On these false memories is erected much of the com

plicated structure of spiritualism, second sight and other similar phenomena. See IDIOCY; PERSONALITY AND ITS DISORDERS; SPEECH, DEFECTS OF; and RETENTIVENESS.

Bibliography. Baldwin, 'Dictionary of Psychology and Philosophy; Freud, 'Psychopathology of Every Day Life (chapter in "Forgetting," 1917); Ribot, 'Diseases of Memory); Guillon, 'Les Maladies de la Mémoires,' with full consideration of hyperamnesia (1897); Sallier, Troubles de la Mémoire) (1892), and Pardo, 'I disturbi della memoria' (1899).

SMITH ELY JELLIFFE, M.D.

MEMPHIS, měm'fis, Egypt, an ancient city near the apex of the Nile Delta, 12 miles south of Cairo, according to Herodotus, founded by Menes, the first king of Egypt. It was a large, rich and splendid city, and the second capital of Egypt. After the fall of Thebes it became the sole capital. Among its buildings the temples of Ptah, Osiris, Serapis, etc., and its palaces were described as remarkable. At the time of the conquest of Egypt by Cambyses (524 B.C.) it was the chief commercial centre of the country and was connected by canals with the Lakes of Moeris and Mareotis. With the rise of Alexandria the importance of Memphis declined, and it was finally destroyed by the Arabs in the 7th century. In Strabo's time (20 A.D.) it was, in population and size, next to Alexandria; in biblical history it is mentioned as Moph and Noph. The name Memphis is a corruption of Men-nofer, "good abode." Edrisi, in the 12th century, describes its remains as extant in his time. Among the works specified by him are a monolithic temple of granite 132 feet high, 12 long and 7 broad, entirely covered within and without with inscriptions, and statues of great beauty and dimensions, one of which was 45 feet high, of a single block of red granite. These ruins then extended about nine miles in every direction, but the destruction has since been so great, chiefly for the construction of Fostat, an Arabic city on the opposite bank of the Nile, that although Pococke and Bruce fixed upon the village of Mitrahineh as the site (where prone on a mound are two colossal statues of Rameses II), this was not accurately ascertained until the French expedition to Egypt, when the discoveries of numerous heaps of rubbish, of blocks of granite covered with hieroglyphics and sculpture, and of colossal fragments scattered over a space of three leagues in circumference, decided the matter. views of the great temple of Ptah, the palace of Apis, the sepulchre of the Apis bulls, portions of the White Wall and of pyramids have been identified. Consult Petrie and Walker (in 'Publications,' Egyptian Research Account, London 1908).

The

MEMPHIS, Mo., city, county-seat of Scotland County, on the Keokuk and Western Railroad, about 160 miles north by west of Saint Louis. It is in an agricultural region, and is the trade centre for a large part of Scotland and adjacent counties. The principal outgoing shipments are farm products and livestock. There are bituminous coal fields in the vicinity. Pop. 2,400.

MEMPHIS, Tenn., city, county-seat of Shelby County, on the Mississippi River, at the

head of all-the-year-round navigation, is the largest city in Tennessee, the fifth in size of the cities on the Mississippi River and the most important commercial centre and distributing point between New Orleans and Saint Louis.

Communications.- Steamer transportation on the Mississippi River and its tributaries reaches all the river and gulf ports, connecting with New Orleans, 394 miles; Mobile, 383 miles; Galveston, 661 miles; Savannah, 665 miles; Charleston, 726 miles; Norfolk, 961 miles; New York, 1,158 miles. Ten trunk lines operating 17 railroads, with two bridges over the Mississippi River, include the Illinois Central; Frisco Railroad; Louisville and Nashville; Nashville, Chattanooga and Saint Louis; Yazoo and Mississippi Valley Railroad; Southern Railway; Missouri Pacific Railway; Saint Louis and Southwestern Railway; Mobile and Ohio Railway; and the Rock Island Railway. The principal inland cities reached by direct lines are Birmingham, 251 miles; Saint Louis, 305 miles; Louisville, 380 miles; New Orleans, 394 miles; Atlanta, 417 miles; Kansas City, 484 miles; Cincinnati, 497 miles; Chicago, 534 miles; Washington, 931 miles. The Cumberland Telephone and Telegraph Company (Bell System) has 18,547 telephones in Memphis served by three exchanges. There are a total of 133 long distance circuits connected with the Memphis exchange, and subscribers are connected with the lines of the Bell System, which covers the entire United States and Canada.

Topographical Conditions.- Memphis is located in the most rapidly developing agricultural section of the country. It is the trade centre from the famous Mississippi Delta, and Saint Francis Basin, the combined area of which is in excess of some of the Eastern States. It is the home of the first successful Farm Development Bureau, which is doing great work in bringing about diversification of crops. The Memphis territory is no longer a one crop country. It now not only grows cotton successfully as before but most all of the other crops that are grown anywhere in the temperate zone. Suburban truck routes operated whereby merchandise of various kinds and produce are handled between Memphis and suburban towns and farms in the Memphis district. This materially simplifies the complex national problem of handling freight on short hauls. The food conservation problem is far better taken care of in this territory, farmers not only feeding themselves but being enabled to make convenient and prompt deliveries of their farm products to the city; this being especially true in connection with dairy products, fruits and vegetables.

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Industries, Commerce, Banking.- Memphis is the largest inland cotton market handling actual cotton in the world. The receipts run between 700,000 and over a million bales per year, according to the size of the crop. These receipts will be very materially increased when the opening of the 10,000,000 acres of land in the Saint Francis Basin is finished. This basin has been protected by secure levees and is being rapidly developed. As a market for short fibre cotton, such as linters and cotton hull fibre, there is no market that can compare with Memphis. There are more fibre mills in Memphis than in any other city and the trade in linters is far above the trade of any other

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market. Over one-half of the total crop of the country is sold through Memphis concerns. This city is the greatest centre for the manufacturing of cotton seed products in the country, including crude and refined cotton-seed oil, meal, hulls and fibre. Memphis also is the largest hardwood producing lumber market. There are in this city 28 hardwood saw mills, with an annual capacity of 370,000,000 feet; 15 lumber yards and 32 woodworking plants. Just outside of the city there are 46 hardwood mills operated by Memphis firms, the capacity of which is 500,000,000 feet. In addition there are many other hardwood mills in the timber districts surrounding Memphis, producing an amount of hardwood lumber equal to the amount manufactured by Memphis firms. Therefore, Memphis may properly be considered as the centre of a production of approximately 2,000,000,000 feet of hardwood annually. A forest products mill has been established in the city, which utilizes slabs, culls and unmerchantable timber into the manufacture of large quantities of wood alcohol and similar products. Charcoal is also produced in large quantities by this mill. The manufacture of sweet feeds is becoming an important industry in Memphis. Cotton-seed products, alfalfa and molasses are produced abundantly in this territory. This industry is being rapidly advanced by the present system of diversified farming. Foreign exports aggregate approximately $100,000,000 yearly, including three-quarter million bales of cotton and 5,000 cars of lumber.

There are 800 manufacturing industries of all kinds in Memphis and its suburbs. These include cotton-seed-oil mills, ice factories, grain elevators, wholesale grocery houses, wholesale dry goods houses, wholesale drug houses, furniture factories, woodworking establishments of all kinds, foundries, machine shops, flour mills, pulp and paper mills, fibre plants, saddlery and harness factories, potteries, car works, pump works, wagon and carriage shops, pure food products, bread, cracker and candy factories, patent medicine works, sugar plantation machinery works, barrel and skewer factories, spoke factories, golf stick works, shuttle block works, trunk, screen door and window factories, basket and box factories, egg case works, horse collar factories, engine and boiler works, electric supplies, refrigerator and cold storage machinery works, cotton gins, stove and range factories, handle and coffin factories, shaft and pole works, cider presses, distilleries and breweries. Memphis has the largest automobile wheel factory in the world. Memphis also is one of the great horse and mule markets of the world.

There are 18 commercial and savings banks in Memphis; also two industrial loan banks and two private banks. The deposits in the 18 commercial banks at the time of the last report amounted to $75,000,000. The total amount of transactions for the year 1918 amounted to $3,441,112,365. The two largest banks carry deposits of $23,500,000 and $17,000,000 respectively.

Civic Conditions. The city is well laid out and well built. The wide, well-shaded and wellpaved streets, the fine public and private buildings, the parks with numerous large trees, all make the city most attractive. The streets are paved with asphalt, vitrified brick, macadam