Memory.

Manawatu Standard, Volume IX, Issue 19, 20 December 1884, Page 1 (Supplement)

Memory.

By Db. R. Wood Ekown. There is no subject of Nature so interesting as psychology. Man, ever since hia crention, has been trying to penetrate the mystery mmd, and after thousands of years the subject is just as obscure as it was to tho first investigator. The physiologist alone has been rewarded, the ps} r chologist is still still striving to wrest from Nature this her most subtle secret. We shall show how memory acts from a physical standpoint, also the theories advanced explanatory of the action of the mind. We may say that memory is an attribute of the mind, bnt it would be more correct to say that they are synonymous, and that thought and imagination aro attributes of > memory. | Science has not,been able to explain the causa- ] tion of memory, but her votaries have done much toward explaining physically tho action of it. It must be remembered, that while the data are voluminous, aud the number of nerve fibers and cells estimated, the conclusions arrived at are m many casos hypothetical as regards the action of memory. Tho metaphysician has done but little, the physiologist almost everything. The most succinct definition of memory I find is Kibot's. He says that " Memory is tha retention' of certain states, their reproduction aud their localization iv the past." We certaiiily eaniwt wisli for a more clear analysis. Physiologists have located the intellect m the gray matter of thc;brain, a- thin crust one-tenth of an inch thick and corhppsed of. convolutions and sulci. It has been estimated that there aro about 300 square inches of gray matter upon both hemispheres. This crust is supported by white matter which is a mass of nerve fibres, and makes by far tho largest part of the brain. Tho gray matter is composed of cells and fibres, which, according to Mr. Bain, number about ono billion and five billions respectively. Those cells and fibres aro the factors of memory, and for distinctiveness at this timo I will denominate them memory cells. An acquisition is a certain thing acquired or learned, and m a richly endowed aud highly retentive mind of, say, two hundred acquisitions, cacli grouping would require five thousand memory cells and twonty-fivc thousand fibres. It must bo reluembered that the brain, besides having memory cells and their associated fibres, is also a

snrl .if battery to furnish power for movements of muscles, acts of energetic volition, and also of foeling. The causation of memory is just as mysterious as that of life. Memory exists, and that is the sum total. Lifo was brought into existence, eith t from a fortuitous combination of oxygen, nitrogen, hydrogen, and carbon, making protoplasm, winch Locarno animated, or by a special divine cci of creatisn. Scientists generally agree that all life must have antecedent life, which to my mind is the only proper solution of biologyThe two most plausiblo theories which account for memory physically aro tho residuum and vibratory. According to tho former theory, when an impression is received l>y a cell, a residuum is left, tha result of a chemical change or decomposition of its protoplasm. When wo look upon a pear, certain cells respond to tho excitation of the impressions of- contour, color, size, and stem ; the result of thia responding is a residuum. If these impressions are repeated often enough, a permanent residuum is formed, and wo havo a memory coll. Decomposition is the act of separating the constituents of a compound. These constituents would bo elementary bodies, but m the above cells th* decomposition is said to leave a residuum, but no explanation is given as regards the action of tho rf sidunm after it is formed. lamat a loss for ! any logical deduction whereby I can understand | the action which goes on m the cell after it has been completely decomposed and a permanent residuum has formed, wldcli under this theory I would call a memory coll. Tho residuum thc-ry I leads ns to the timo when tho cell becomes pel - mancntly changed, but does not enlighten us upon its subsequent action. The vibratory theory explains tho physiological action of memory m a very satisfactory manner. If we look at tho poar, certain colls vibrato from excitation, resultant frsm the impression. We do not have, m this instance, any decomposition or residuum, simply a vibratory movements The cell remains the same, except the moleetfSr arrangement. Whou tho impression ceases, tho cells cease to vibr^le, and obtain a period of rest which is essential to memory. It will bo noticed that llio vibration of a cell is clear to the jrand, because it acts m its entirety, rests, and via'ates again to tho same impression ; each vioration fixes permanently its peculiar movement, and wo have a cell which vibrates to no other impression, and the result is a memory cell. This is much better than tho residuum theory, which leaves a residuum after every cell vibration and eventually a permanent one. When an impression is received upon tho retina, tympanum, tongue, fingers, or olfactory bulbs, it is conveyed by proper nerve filaments to cells m tho gray matter of tho brain. Theso cells vibrato from excitation, arid undergo a change, say that of molecular arrangement. If this impression is repeated often enough, tho molecules are permanently changed, and we have memory cells and remember the impression. If, on tho other hand, the impression is made but once, and then not violently, tho cells assume their first condition and we forget the impression, it passes from our mind. In this connection let me say that m tlio true senso we do not see an object, hear a sound, feel a substance, smell an odor, or taste edibles ; we simply become conscious of the impression when they irritate to vibration tho cells m the gray matter. These impressions cause duTerent cells to vibrato the same to tho same excitations, which allows differentiation, and memory is the result. If different cells responded to tho sanio impression, there would be no permanency, consequently no cognition. Why do the same cells vibrate to the samo impression? The most plausiblo explanation is molecular change. If wo strike a bar of steel upon tho end with a hammer, we can produce ft magnet. Tho blow causes a change of molecules ] m the steel, and polarizes them. Whether tho j molecules of a cell are simply changed, or polarised, is hard to determine, but that some change takes place by vibration is evident from tho fact that we remember more easily where tho impression is received many times. If tho molecular theory is correct, and every substance is composed of molecules, the whole body of cells m the gray matter would bo no exception. Some men of learning say that the molecules of tho b»dy are polarized m health, and when disarranged disease is the result. If this is true, and nervous force electricity, and the brain the battery, why not say that tho change m a memory cell is molecular ? Why does the samp cell vibrate to the samo impression? Forco or motion travels m tho direction of tho least resistance. When an. impression is carried along a nerro fibre, there is n certain amount of resistance, and every impression weakens its power to resist, and each succeeding impression travels along the fibre which is attunad to it and has tho least resistance. If tho same impression is carried on the same nerve Hbre, It must necessarily reach the sumo cell, which vibrates according to its molecular change, and wo become conscious of tho impressions. 1 would, m this connection, say that repeated impressions aro not always necessary to produce a memory cell. A sudden violent excitation will cause a permanent change m a cell. We all have oxperiencad sudden impressions which wo have never forgotten, and never have felt but once. To remember is to recur almost instantly without exertion of will, to recollect is to recall by associations, to gather ideas step by step until the impression sought is brought to mind. Wo recollect by association, by a group of cells vibrating which excites another and so on. According to Bain, thoro aro about ono billion colls and fivo billion fibres. These fibres connect cells and consequently groups. It will be readily understood how this occurs, if wo boar m mind how we think ; how ono thought brings another into consciousness. Wo smell a rose, its odor excites certain cells ; through fibre connections other groups are excited to vibration, and wo are conscious of events where the roso assumed a prominent part. We see a face which recalls the name and peculiaiities of ths possessor. We see a house, and recollect tho persons living therein. Tho house causes an impression which excites to vibration a group of cells, which m turn brings other groups into activity and wo know tho occupants. Most of our thought is through association, comparatively little that is instantaneous. In remembering, timo and space are of little value, -but they are essential to recollection. When wo indulge m retrospection, memory carries us back weeks, months, and years. We cannot recollect without time and space. Tho timo is tho present, space the period between the occurronco and the present moment. Wo have a conscious and organised memory. When we perform an act with a distiuct end m ■ view, it is the result of conscious memory. When : a beginner is learning to play upon a piano, every note is struck by the effort of the will, and therefore conscious. In setting our watch, we do it consciously ; we have found the correct timo and our mind is on tho act, and wo turn the hands carefnlly until our aim is accomplished. Therefore .every act of will power is tho result of conscious j memory. Intensity and duration aro indispensable to con- ! scions memory. If one of theso conditions be wanting,- or any other unknown to ns, then consciousness (a part of the whole) would disappear, and that which would remain of tho fact is organized. Intensity is a degree of concentration which may vary, owing to the striving of our states of consciousness to supplant ono another, and victory results either from tho superiority of one or weakness of tho other. Duration is the period between the impression and cons&tfusnes of it. Ribot says it requires 016 to 014 d^ second to hear ; 021 to o*lß of a second to touch ; and o'2o to 0"22 ofgi second to seo. This would indicate that the expression, " quick as thought," is a mere figure of speech. ; Tho acts of organized memory are Jbrformed unconsciously, involuntarily. The odor of food will sometimes cause an increased flow of saliva. When wo were learning to walk, our steps wf-re taken with hesitancy and deliberation — consciously ; now we walk without knowing it, our conscious memory, through continual repetition, lias become organized. If we meet an. obstruction on the sidewalk, wo. uncousciously move to ono side to avoid it. This is tho result of experience. Wo know intuitively that, if we do not turn, we will run into tho obstruction. Intuition and organized memory are to my mind synonymous. Wo raise food to our mouth without consciousness ; this is the result of habit. Habit is resultant from frequent repetitions, which produce organized memory. Upon reflection wo will find that' comparatively few of our acts are conscious. Consciousness is n narrow wicket through which wo are connected with the outer world. I spoke of a group of cells always vibrating to the same impression, and another argument m favor of that statement is the weariness which ensues upon protracted vision, hearing, taste, etc. if different cells responded to the same impression, there would be no weariness. Cells do become tired and refuse to act. If we look upon ouc color continually it becomes blurred, ono continual sound becomes indistinct, tho odor from a flower is at first acute, aiterward less fragrant. This would indicate two things ; first, that the same cells respond to the same impressions ; second, that memory colls must have rest. This rest is givein.by exercising different faculties and by sleep. But' even m sleep this result is not always attained, for wo often dream, and dreaming is cell activity during sleep. This is proved by tho fact that wo never dream of anything but past events. Physiologists have proved that during sloop the brain is pale from want of blood, but if tho sleeper dreams it is a brighter red. This would indicato au activity of tho brain during dreaming. One of the peculiarities ef dreaming is tho extremely

brief period which i^i required, also it tiilcos no noto of timo or sp:tc<\ A drop of water has caused a dreamer to travr-1 thousands of miles, to drown iii a lake mid to wake him up. A gentleman m this audience; onec dreamed " that ho was walking through a slroot, and (-topped heforo a hardware stoic m which wcro stoves arranged hi tiers on;---above another; while looking at them they fell with a terrific crash to tho floor." Another student throwing a box down stairs ciinso.il this dream and awakened the dreamer at tho r.rune time. Dr. Carpenter relates Iho case, of a cle-rgv-man who fell asleep m tha pulpit, awaking wilh tho idea that ha had slept for more than an hour ; but on referring to his hymn bsok, ho found that his sleep had lasted through the singing of a single