THE 
 
 MENTAL SYMPTOMS 
 
 OF 
 
 FATIGUE 
 
 By EDWARD COWLES, M.D. 
 Medical Superintendent of the McLean Hospital 
 SOMERVILLE , MASS. 
 
 Reprinted from the Transactions of the New York State Medical Association 
 
 New York 
 
 FLESS & RIDGE PRINTING CO. 
 
 Fifth Aye. and 16th St. 
 
 1893 
 
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 THE MENTAL SYMPTOMS OF FATIGUE. 1 
 
 The subject of mental symptoms carries with it the 
 suggestion of something vague and difficult of appre¬ 
 hension. The study of mental disorders is forbidding to 
 the general physician who feels that he has neither time 
 nor patience for it. The present purpose is to contribute 
 something to a better understanding and an easier ap¬ 
 preciation of the mental symptoms of fatigue, which will 
 be considered under the following heads : (1) the nature 
 of mental symptoms; (2) the physical conditions of 
 fatigue ; (3) some elementary facts of the nervous and 
 mental mechanism ; and (4) the alterations of mental 
 functions that are significant as symptoms. 
 
 1. THE NATURE OF MENTAL SYMPTOMS. 
 
 1 
 
 
 
 
 It lias been the fashion to regard this branch of neu¬ 
 rology as being slow in its progress, having no coherent 
 principles, resting upon an indeterminate basis, and as 
 being unscientific in its classification and therapeutics. 
 Krafft-Ebing admits that the anatomy of the nervous 
 system has so far been incomplete and unsatisfactory in 
 not enabling us to reason from structure to function, as 
 has been done in the relatively simple structure of the 
 vegetative organs; and that pathology has been disap¬ 
 pointing in failing to explain the most marked disturb¬ 
 ances of function. But he points to the fact that 
 psychiatry is one of the youngest of our special sci¬ 
 ences. He says it seems almost exclusively dependent 
 
 
 w 
 
 1 Read before the New York State Medical Association, November 1G, 
 1892. 
 
2 
 
 THE MENTAL SYMPTOMS OF FATIGUE. 
 
 on itself, and is limited to the direct observation of mor¬ 
 bid mental phenomena ; also that it is from the empirical 
 valuation of these phenomena that we are obliged to 
 draw conclusions as to the kind and degree of the func¬ 
 tional disturbance in the organ of mind. His conclusion 
 is that great progress has been made in the raising of 
 psychiatry to the rank of a natural science with methods 
 of empirical research. Its direct advancement can be 
 accomplished only by tireless observation and report of 
 clinical phenomena, and thus fixing the facts of the 
 mental life. While mental disease is always brain dis¬ 
 ease, the course of the processes in mental disorders is 
 discovered through observation, as in any other disease. 
 
 The hope of gaining a clearer appreciation of mental 
 symptoms lies in the fact that we may observe so much 
 more directly the manifestations of mind, and conse¬ 
 quently of nervous function, than we can those of any 
 other function of the nervous system. We may study, 
 by the aid of anatomy, physiology, pathology, and 
 physics, an involuntary mechanism like the heart; or 
 the action of the muscular system as a voluntary mech¬ 
 anism. In the action of the peripheral apparatus we 
 note the expression of the setting free of central nervous 
 energy, and can trace the conducting path of the motive 
 energy back to motor centres. But we can get no further 
 than to speak of 4 4 innervation ’ 5 and 4 4 inhibition ’ ’ with 
 entire ignorance of the way in which nervous substance 
 is stimulated, and augments or controls that which 
 stimulates it into activity. We are conscious that the 
 mode of expression of the active mind through the 
 peripheral instruments is indirect. 
 
 All this is true also of the complex organ of speech, 
 when examined as an organ, and as one of the minor 
 mechanisms of whose anatomy and pathology we may 
 make the most scientific study, as we need to do for a 
 correct interpretation of any change from normal action. 
 But through this organ we hear in the articulate sounds 
 with varied tone, pitch, and inflection, and in the words 
 
THE MENTAL SYMPTOMS OF FATIGUE. 
 
 3 
 
 which this instrument produces, the direct expression of 
 a function by which brain cells are able to convey to our 
 understanding the largeness and fineness of meaning 
 that is comprehended in the “infinite variety” of the 
 human mind. This takes us into a field of phenomena 
 that our kindred sciences fail to reach. Instead of 
 lamenting that they do not aid us, it is perhaps more 
 true to say that we do not need their aid in the interpre¬ 
 tation of these manifestations, which, by a superior mode 
 of expression, convey finer variations of meaning, and 
 make revelations of earlier and slighter departures from 
 normal action than we can get from any other function 
 of the human organism. Moreover, it is given us to 
 make these discriminations by the natural law of mind, 
 without any need of laborious study and interpretation 
 of the working of an intervening instrument. We hear 
 the expression of thought and feeling in sounds that we 
 come to know, and we need not stop to note the mech¬ 
 anism of their utterance. From the moment when we 
 are thrust into this noisy world, the articulate sounds of 
 the human voice begin to be familiar to us. Every man 
 makes his way in the world largely by his success in 
 measuring the minds of his fellow-men. We have, by 
 nature, a most intimate common knowledge of variations 
 in mental function ; of no science have we a more prac¬ 
 tical every-day knowledge than of psychology. It is 
 true that we have to discover a way to reduce the data 
 of this knowledge to orderly form, and to recognise the 
 import of commonly observed mental manifestations by 
 observing their correspondence with recognised bodily 
 conditions. This must constitute a true science of the 
 health and disease of a function which has its own 
 peculiar character and physiological laws. 
 
 The nature of mental symptoms, or manifestations of 
 departures from normal functions, being thus under¬ 
 stood, we should approach their study with minds free 
 from prejudice, prepared to observe and fix the facts of 
 each kind of manifestation and array them in the order 
 
4 THE MENTAL SYMPTOMS OF FATIGUE. 
 
 of their occurrence and relations with each other. The 
 question now comes, can we set up a plain and intelli¬ 
 gible conception of the normal mental mechanism that 
 will serve as our standard in which to note and localise, 
 as it were, the departures from normal action? We 
 must begin in an elementary way, and deal first with 
 the slighter variations from conditions of health in the 
 mechanism, and its fullness of power to do what it can 
 do. In the brief time allotted here, the attempt will be 
 made to do little more than to point out a method of 
 observation and study on the basis of some of the prim¬ 
 ary facts of the mental and nervous mechanism. 
 
 2 . THE PHYSICAL CONDITIONS OF FATIGUE. 
 
 The proposition may be laid down to start with, as a 
 working formula, that the organ of the mind is an appar¬ 
 atus for the storage and discharge of nervous energy, 
 and that all mental symptoms indicate a failure of the 
 
 mental elements to functionate with normal co-ordi- 
 
 / 
 
 nation, because of modification of the power to set free 
 nervous energy, due to lack of the discharging force, or 
 the obstruction of it, or to lessened power of control; or 
 as due to excess of stimulation and discharge, which 
 means also relative weakness of inhibitory control. All 
 of these conditions of nervous action may exist together, 
 or side by side, and often do, not only in the most mani¬ 
 fest of mental diseases, but in the lesser degree of ner¬ 
 vous fatigue. In fact the key to the understanding of 
 these graver conditions seems to be in the appreciation of 
 the slighter degree of nervous exhaustion always to be 
 observed in normal fatigue. The condition of the cen¬ 
 tral organ may be directly observed through the mental 
 symptoms which quickly reflect the variations in nervous 
 force and activity. The correct understanding of these 
 symptoms is essential to the best treatment of nervous 
 exhaustion in all its forms. And this is the soil in which 
 the more serious nervous diseases take root and grow. 
 
THE MENTAL SYMPTOMS OF FATIGUE. 
 
 5 
 
 The bodily conditions of fatigue should first be con¬ 
 sidered as far as we can know them, and may be studied 
 in their two forms of degrees : (1) normal fatigue , or th 
 condition of wholesome tire from daily physiological 
 use ; and (2) pathological fatigue , or the condition of 
 persistent “ impoverishment of nervous tissue in excess 
 of repair,” according to Beard, which constitutes nervous 
 exhaustion or neurasthenia. The mental symptoms are 
 to be studied in their close and direct correspondence 
 with these conditions of fatigue. 
 
 The effects of fatigue are produced by sufficiently con¬ 
 tinued exercise in the physiological use of any func¬ 
 tion, muscular or nervous. The sense of fatigue is com¬ 
 plex, and may have a central or peripheral source, or 
 both together. In muscular tissue the condition of 
 fatigue depends upon the physiological fact that muscu¬ 
 lar contraction is in some way or other the result of a 
 chemical change, whereby the latent energy is set free 
 and expended in the mechanical work, with also the 
 setting free of heat. The resultant chemical products 
 are toxic, and obstructive of muscular function unless 
 they are duly washed away in the blood current; and 
 time must be given in rest and sleep for this process, as 
 well as for nutrition and repair. These toxic products 
 being variously irritant or benumbing, doubtless thus 
 affect the sensory apparatus through which fatigue is 
 felt. It is evident from this that the condition of mus¬ 
 cular fatigue has always a dual character—there is direct 
 expenditure of energy, requiring repair, and a toxic 
 element that may be obstructive of function, both that of 
 discharging energy and of taking up nutrition. 
 
 In nervous substance, the nature of nerve force being 
 unknown, the effects of the passage of a nervous impulse 
 along nerve-fibres are not demonstrable as attended by 
 chemical changes, or loss of normal irritability as a 
 manifestation of fatigue. 1 But in the central nervous 
 organs it is found that their function is dependent on an 
 
 1 Bowditch, Jour, of Phys., Yol. 6, p. 133. 
 
6 THE MENTAL SYMPTOMS OF FATIGUE. 
 
 adequate supply of oxygen, and this implies that “in 
 nervous, as in muscular substance, a metabolism, mainly 
 of an oxidative character, is the real cause of the develop¬ 
 ment of energy.” 1 In fact we do not doubt that toxic 
 waste products attend upon central nervous activity, and 
 this accords with the biological theory that all function 
 is due to chemical changes taking place within the 
 organism, and thatjthe functional activity of a specialised 
 tissue dex>ends primarily upon the changes in its indivi¬ 
 dual cells. The dual character of all conditions of pri¬ 
 mary fatigue is evident, as is also the importance of 
 recognising the effects of the self-produced poisonous 
 substances that regularly result from the chemical 
 changes in tissue metabolism within the body, as we are 
 taught by the brilliant revelations of modern chemical 
 physiology and pathology. 
 
 Normal fatigue from the discharge of tissue energy 
 is therefore shown to be inseparably accompanied by 
 toxic products that contribute to the effects of fatigue. 
 Pathological fatigue represents a further development 
 and persistence of this condition in the organism. Stimu¬ 
 lation too soon repeated, without giving time for rest and 
 repair, finds nerve-cells in fatigued areas having less 
 power to act because of inanition from deficient rest and 
 nourishment; they are also hindered in action by the 
 incomplete removal of the toxic products of previous 
 action. Then assimilation is further hindered, first, by 
 the lessened nutritive quality of the blood from the 
 presence of non-eliminated toxic materials ; and sec¬ 
 ondly the probable toxic weakening of the cells’ power 
 to assimilate the nutrition that is furnished to them. 
 The development of a manifestly morbid condition may 
 be very slow and insidious, or more rapid, according as 
 the balance of the processes of constructive and regres¬ 
 sive metabolism are more or less on the side of impover¬ 
 ishment, exhaustion, and weakness. From the gradually 
 failing elimination, the local inanition may become more 
 
 1 Foster, Physiology, 5th Eng. Ed., 1890, pp. 914-918. 
 
TEE MENTAL SYMPTOMS OF FATIGUE. 
 
 7 
 
 general, and the first results are an increased excitability 
 from weakened resistance and inhibition, with a quick 
 exhaustion of the nervous system under exercise. These 
 are the constant characteristics of neurasthenia. Thus, 
 as Kowalewsky 1 says, “a locally limited over-strain of 
 a certain part of the nervous system may lead to general 
 exhaustion and neurasthenia.” Hence neurasthenia has 
 been defined by Ziemssen 2 as “a functional weakness of 
 the nervous system, varying from the slightest degrees in 
 simple localities to entire loss of strength in the whole 
 nervous system.” Arndt 3 states the characteristics of 
 neurasthenia to be “ increased excitability with a ten¬ 
 dency to rapid fatigue, especially of the muscular sys¬ 
 tem.” He notes particularly, also, the cerebral irrita¬ 
 bility, and hyperaesthesia of the cranial nerves, especially 
 those of special senses. 
 
 The remarkable experiments of Hodge 4 are most sug¬ 
 gestive as demonstrating the physiological shrinkage and 
 recovery of cell contents in spinal ganglion cells ; it is 
 shown that upon stimulation and upon normal exercise, 
 the histological changes of breaking down and building 
 up of cell contents are accompaniments of the physio¬ 
 logical discharge and re-storage of energy, and as being 
 normally attendant upon fatigue followed by rest. 
 
 The conditions of the organism in normal and patho¬ 
 logical fatigue being thus understood, we have a basis 
 for the study of the relation thereto of the mental symp¬ 
 toms of fatigue. It is agreed by all observers that the 
 symptoms of nervous exhaustion are mainly subjective. 
 The objective symptoms need not be dwelt upon here ; the 
 commonly noted manifestations of increased excitability, 
 irritability, and restlessness, are readily recognised as 
 representing the internal hyperaesthesia so significant of 
 the “irritable weakness” of nervous exhaustion. The 
 
 1 Centralblatt, f. Nervenheilkunde, October, 1890. 
 
 2 Neurasthenia, Wood’s Monographs, Yol. 1, 1889, p. 534. 
 
 3 Art., Neurasthenia, Tuke’s Diet. Psych., Med., 1892, Yol. 2, p. 843. 
 
 i Amer. Jour, of Psychol., May, 1888 ; May, 1889 ; and February, 1891. 
 
 Also, Jour, of Morphology, November, 1892. 
 
8 
 
 THE MENTAL SYMPTOMS OF FATIGUE. 
 
 purpose now is to show the significance of a few easily, 
 and in fact commonly, recognised subjective or mental 
 symptoms, which stand as distinctive signs of fatigue. 
 They furnish a ready index of the fatigue and auto¬ 
 intoxication of nerve and muscle tissues as a guide for 
 diagnosis, prophylaxis, and treatment; and the general 
 symptoms of nervous exhaustion can be understood 
 better and earlier by the proper interpretation of the 
 mental symptoms. 
 
 3. SOME ELEMENTARY FACTS OF THE NERVOUS AND 
 
 MENTAL MECHANISM. 
 
 In order to make clear the changes, that we call symp¬ 
 toms, in the mental manifestations, it is necessary to 
 note some elementary facts in the relations between the 
 functions of the mind and body. While they are very 
 complex in their detail, there are still certain broad gen¬ 
 eralisations that we could readily grasp but for the 
 difficulty of keeping a number of the elements alike 
 prominent in our minds at the same time, while studying 
 their inter-play. This may be aided, with some exercise 
 of the imagination, by the tabulated diagram here pre¬ 
 sented. It is designed to represent the nervous and 
 mental mechanism , and to show some of the relations of 
 the inner activities that we call mental, to the body in 
 general, and to the environment. 
 
 Let us suppose that we can look into the region of con¬ 
 scious mind as into an enclosed place, and a section being 
 made of it we can see noted thereon, as in the “ field of 
 consciousness,” the modes of mental action as they are 
 designated by common agreement. At the other end of 
 the diagram are noted the organs of special sense through 
 
 « 
 
 which stimuli from the environment start impulses that 
 are conducted along sensory tracts, and produce physical 
 sensations in the sensory centres in the entrance to the 
 field of consciousness. When these sensations are in¬ 
 tense enough to pass over “the threshold” of the field of 
 
THE MENIAL SYMPTOMS OF FATIGUE. 9 
 
 
 NERVOUS AND MENTAL MECHANISM 
 
10 
 
 TEE MENTAL SYMPTOMS OF FATIGUE. 
 
 consciousness, there is a conscious mental perception of 
 such sensations, as of sight, hearing, and the like. This 
 is the initial event of the process by which we mentally 
 see, perceive, and know, something in the environment; 
 there is, through sensory action, the presentation in our 
 field of consciousness, and the perception of what we call 
 the image or idea of the external thing. But we may 
 immediately remember that we have seen the same object 
 before, and we become conscious of an action of memory , 
 by which we retain impressions previously received, and 
 can recall them by the law of association of ideas. We 
 image them again, or imagine them. Thus a complex 
 mode of mental action arises; there is consciousness , then 
 conscious perception of a sensation, as from the sense 
 of sight, and the memory , acting all together. Hard 
 upon this comes the higher process of ideation or intel¬ 
 lection, the comparing process, by which we conceive 
 abstract notions of things, judge them by comparison, 
 and reason about them. All these may be included also 
 in the mode of consciousness along with perception and 
 memory, and form parts of a complex process of knowing, 
 or intellection, although we name them as separate 
 actions. Whenever we talk with a man, we gauge and 
 test minutely all these operations of his mind with great 
 practical accuracy. We estimate his mental quality and 
 power ; we judge the man by what his mind can do. 
 
 One of the points of present interest is now before us; 
 as the antecedent fact in the mental process just described, 
 we must premise the state or existence of conscious¬ 
 ness, without which there can be no mental action. We 
 may say that there is latent consciousness in an unborn 
 infant, that soon after enters upon conscious life ; then 
 consciousness springs into action, and the first percep 
 tion is likely to be of sensations from the sense of touch. 
 But active consciousness is always attending to some 
 presentation in its field, to the more or less complete 
 exclusion of other presentations. While the multitude 
 of sensations are thronging into the sensorium through 
 
THE MENTAL SYMPTOMS OF FATIGUE. 
 
 11 
 
 all the organs of special sense, the attention , being fixed 
 upon some intensified perception, excludes all but this 
 intensified one. The same is true of a presentation of 
 memory, or of a process of reasoning ; or all these may 
 be involved in a complex object of attention. When¬ 
 ever, by the action of what we call the attention, we hold 
 in mind a perception, a memory, or the data of a process 
 of reasoning, we are exercising the memory also in the 
 very act of retaining all these elements of the mental 
 process^ On the other hand we know that by the atten¬ 
 tion we can control the memory, by controlling and 
 changing the flow of ideas it recalls; and all this 
 goes to show the inseparable working together of these 
 processes. 
 
 The attention is a mental element of the greatest 
 interest, and is commonly regarded as meaning a “con¬ 
 centration of consciousness. ’ ’ According to Sully 1 it may 
 be defined as the active intensification of consciousness 
 in particular directions. Whatever, at any time, 
 “occupies the mind,” is for the moment the supreme 
 object of attention. The attention is one with active 
 consciousness, and is often described as accompanying 
 every other mental action. 
 
 It is a common experience, in revery and in dreams, 
 that a spontaneous flow of ideas is continually passing 
 through the mind ; one item follows another in the 
 train of associated ideas through the working of memory 
 and imagination by the laws of habit and association, 
 without direction or control. The attention is then said 
 to be acting in one of its two forms, and this form is 
 spontaneous attention. It is also called reflex attention , 
 as it acts by being attracted to the idea or object in the 
 mind that most interests it, or keeps it on the alert, or 
 stimulates it. The idea may be intensified in interest 
 by pleasurable or painful feeling , by a desire or a fear. 
 The act itself of attention to such an object of thought, 
 increases the intensification of it, and tends to keep 
 
 1 Art., Attention. Tuke’s Diet. Psych. Med., Yol. 1, p. 106. 
 
12 TEE MENTAL SYMPTOMS OF FATIGUE. 
 
 ideas of kindred nature in the mind ; the mind dwells 
 upon them, is absorbed in them. 
 
 Voluntary attention is the other form of this mental 
 function ; and this is at the very centre of interest in 
 this inquiry, ft is spontaneous attention with the added 
 power of direction and control ; the attention is thus in¬ 
 separably associated with the will, volition, or control¬ 
 ling power. The essential fact is that in voluntary atten¬ 
 tion lies the mental activity of inhibition ; it is inhibition 
 working through attention. According to Foster, just 
 as physiological inhibition plays its part in the lower 
 mechanisms of the body, so is it important in the whole 
 work of the central nervous system. Also, just as all 
 voluntary muscular actions are under the control of an 
 attending will, so is the directing and concentrating of 
 the attention upon a chosen thought an act of volition. 
 A man controls his own mind by willing his attention, 
 as it were, to be fixed upon some one item or object, in 
 the train of presented ideas, to the exclusion of others. 
 He thinks about what he chooses to think about, and 
 inhibits mind wandering. He may make the most 
 worthy object interesting*^ this is intensified by holding 
 in mental view its worthiness, and thus the attractions 
 of less worthy interests and emotions are resisted. 
 
 Sully says it is pre-eminently by acts of attention that 
 all the elaborative work of thought is effected, and that 
 the attention is^ the great conditioning factor in our intel¬ 
 lectual life ; all great intellectual achievement involves 
 energy of will acting as voluntary attention. The student 
 attains to this power by training and education of his 
 higher mental control; the man who chooses the path of 
 wisdom and rectitude exercises and strengthens his 
 power of voluntary attention by the practice of self-con¬ 
 trol in inhibiting the impulses of his passions? Thus it 
 is that voluntary attention is in close relation with the 
 highest as well as the latest developed acquirements of 
 the mind, in its power to use the force of nervous energy 
 to the best effect. It is well known that the latest 
 
THE MENTAL SYMPTOMS OF FATIGUE. 
 
 13 
 
 acquirements are soonest impaired with the abatement 
 of normal energy. 
 
 Every exercise of the will in attention is accompanied 
 by the expenditure of energy, and by the “ sense of 
 effort ’’that occurs, particularly when the attention works 
 against some resisting motive, interest or feeling. This 
 directing and inhibitory control is at its best in the equi¬ 
 librium of health of mind and body, and therefore it is a 
 most important means of estimating mental health and 
 vigor; mental disorder is commonly attended with dis¬ 
 turbances of the normal process of attention, as will 
 directly appear in the discussion of mental symptoms. 
 This constitutes one of the points of great diagnostic 
 value. 
 
 We have, so far, concerned ourselves in this discussion 
 quite exclusively with the processes of knowing or intel¬ 
 lection. But we are always conscious of another order of 
 mental phenomena, the feelings , and they are of pleas¬ 
 ure or of pain, or they may be in varying degrees agree¬ 
 able or disagreeable. From the lower forms of bodily 
 pleasure and pain, upward in the scale to those aroused 
 by the perceptions of color and music, the feelings are 
 said to be “ corporeal.” But the purely mental feeling 
 that always attends upon pleasurable or painful ideas, is 
 inseparable from them. Without ideas there can be no 
 such feeling ; and according to its intensity, a feeling of 
 pleasure or pain intensifies the idea it accompanies, and 
 makes it prominent in consciousness, tending to attract 
 more strongly, and to hold, the attention. Thus, as has 
 already been shown, there may be an antagonism between 
 worthy and unworthy ideas and feelings, or in the moral 
 sense of right and wrong, with need of the inhibitory 
 power of voluntary attention to choose, control, and 
 guide conduct. This brings out the opposing factors in 
 the operation of will, attention, ideas, and feelings. The 
 feelings excited by ideas prompt to action, which may 
 be inhibited or augmented by an opposing or consenting 
 will. 
 
14 tiie mental symptoms of fatigue. 
 
 Referring now to the diagram, the relations of these 
 activities are seen to be noted in their natural order. 
 Feeling follows upon intellection, and all the included 
 mental activities are operating in the field of conscious¬ 
 ness. The outcome of this interplay is in the union of 
 willing with acting at the point where the resultant of 
 the mental forces appears to act upon the motor centres, 
 or stimulate in them the impulses that end in the setting 
 free of muscular motion. Thus the picture of the “ nerv¬ 
 ous circle ’ 5 is now complete, and shows the working of 
 the nervous and mental mechanism under the stimula¬ 
 tion of sensations through the special senses. Then con¬ 
 sciousness, through the attention (these two being gen¬ 
 eral states, or modes of mental action), knows, or “sees ” 
 in the very mind’s eye, the special modes of action which 
 we call sense-perception, memory, reasoning, feeling, and 
 the willing of motor impulses which end in muscular 
 motion. This completes the “ circle.” 
 
 The sensations from the special senses are those of 
 which we are most conscious; they are of high intensity, 
 but we little realise that they are small in volume com¬ 
 pared with the great inflow of organic sensations of 
 which, in normal conditions, we are not conscious. 
 These organic sensations, that, according to Ribot, give 
 us the sense of body , or of personality , are of low inten¬ 
 sity but vast in volume ; proceeding from every minute 
 part of the tissues and organs of the body, their inflow, 
 along sensory tracts, enters the sensorium beneath the 
 “threshold of consciousness” into the region of sub- 
 consciousness. Their origin is shown in the sources 
 noted in the fainter letters in the diagram, and their 
 course by the dotted lines. The muscular sense, which 
 is complex in its origin, includes feelings that afford an 
 example of the more pronounced of these organic sensa¬ 
 tions. Thus, we get the sense of weight and posture. 
 Again there are those not felt in normal conditions, 
 but, like hunger and thirst, which are general in their 
 origin, may become intensified so that at times there is 
 
THE MENTAL SYMPTOMS OF FATIGUE. 
 
 15 
 
 consciousness of tliem. There are still others, as in the 
 morbid conditions of hyperaesthesia, and paraesthesia, 
 that appear as pain or a general feeling of misery ; they 
 are vague in character, and their sources often can not 
 be determined. 
 
 These organic sensations, and their alterations, are of 
 such a nature that they afford another point in the nerv¬ 
 ous and mental mechanism of great diagnostic value. In 
 normal states, when all is well with the organism in the 
 equilibrium of health, they constitute the sense of well¬ 
 being. Here again we have an important means of meas¬ 
 uring any falling olf of nervous vigor ; from the slighter 
 alterations of bodily feelings in fatigue to those that 
 create a persistent sense of ill-being, these changes cause 
 variations in the ‘ £ emotional tone ’ ’ that are the most 
 sensitive indices of the degree of fatigue and exhaustion, 
 both normal and pathological. The emotional tone is 
 thus seen to be affected in two ways. There may be, in 
 health, all degrees of pleasurable or painful mental feel¬ 
 ing, between the extremes of exaltation and depression, 
 according to what one has to think about; in this case a 
 lowered emotional tone from grief or care may be a pass¬ 
 ing event, or if prolonged, may have a directly debilitat¬ 
 ing effect upon the organism through the motor tract 
 of the nervous system. The stimulant and dejnessant 
 effects of the natural emotions upon the circulatory sys¬ 
 tem and upon bodily health in general, are well enough 
 known. On the other hand, a persistent state of morbid 
 dejuession of feeling may be no more than the mental 
 concomitant of bodily ill-being, however it may have 
 been induced. There may be three events in the train : 
 first, undue care, real trouble, and anxiety or grief may 
 initiate a general condition of ill-being, which, in turn, 
 may be the cause of morbid depression as the third 
 event. The first in this order may be entirely wanting, 
 but the condition of ill-being, through impairment of 
 health and nervous vigor, must exist from some cause 
 before the strictly morbid mental symptoms can appear. 
 
16 
 
 THE MENTAL SYMPTOMS OF FATIGUE. 
 
 4. THE ALTERATIONS OF MENTAL FUNCTIONS THAT ARE 
 
 SIGNIFICANT AS SYMPTOMS. 
 
 It now remains to describe the special alterations in 
 some of these prominent factors of the mental mechan¬ 
 ism, and their significance in conditions of normal and 
 pathological fatigue. In normal fatigue it is to be 
 kept in mind, that the dual physical condition is one 
 of the expenditure of nervous energy in work to the 
 immediate fatigue of nerve cells, and the accumulation, 
 locally and in the circulatory system, of toxic waste 
 products ; and that the processes of nutrition and elim¬ 
 ination require time and rest. The mental concomitants 
 of this condition are: a diminished sense of well- 
 being^ or a feeling of fatigue, sometimes amounting to 
 a sense of ill-being , which includes in its complex causa¬ 
 tion the influence of the toxic elements. The emotional 
 tone is lowered, and there is less vivacity of feeling. There 
 is also lessened mental activity in general. Voluntary 
 attention is fatigued; that is, the mental inhibition is 
 lessened, with diminished control over the attention, and 
 one is conscious of an extra sense of effort in mental 
 work. There is “mind wandering.” The logical pro¬ 
 cesses work more slowly and with less effect in making 
 comparisons and judgments, and in reasoning to conclu¬ 
 sions ; the tired attention holds on with effort to one 
 member of a proposition, while another slips away^ 
 There is a consciousness of mental inadequacy and diffi¬ 
 culty in keeping awake. This is the common experience 
 of evening tire. Restoration follows upon a due amount 
 of rest, sleep and nutrition, and the somnolence disap¬ 
 pears when the acid waste products, etc., in the circula¬ 
 tion are removed. 
 
 The condition of pathological fatigue is induced 
 when the process of restoration is continuously incom¬ 
 plete. Then we have to conceive of deficient nutrition 
 and an irritating intoxication as both contributing to the 
 “ irritable weakness,” which is a manifestation of the 
 characteristic hyperaesthesia. We may now note the 
 
TEE MENTAL SYMPTOMS OF FATIGUE. 
 
 17 
 
 significant alterations of the feelings, the irritability of 
 temper, the weakening of the power of voluntary atten¬ 
 tion, and the effects of these alterations. The patient 
 may complain of painful or miserable bodily sensations, 
 hyperaesthesia and restlessness ; and often of paraes- 
 thesia in various forms. The symptoms may be ana¬ 
 lysed and classified according to the order of their 
 appearance, and the functions affected. 
 
 The first order of mental symptoms of pathological 
 fatigue, in the importance and earliness of their appear¬ 
 ance, may now be noted. These most obvious mental 
 signs are the characteristic depression of feeling , a low¬ 
 ering of the emotional tone , and a sense of ill-being. 
 
 The symptoms quickly reflect debilitated bodily con¬ 
 ditions that are the sources of the “ miserable feelings.” 
 These subjective indications are often the only ones of 
 the existing exhaustion in its complex character. Again, 
 they are corroborative of a suspicion of general neuras¬ 
 thenia when complaint is made of some local functional 
 disorder ; in other words, local disorder is often shown to 
 be simply an expression of general neurasthenia, of which 
 the only diagnostic evidence is in the mental symptoms. 
 
 The second order of mental symptoms, in time of 
 appearance, is usually the persistent decrease of the 
 power of voluntary attention (reflex attention ), and 
 sometimes of memory; there is also the sense of in¬ 
 adequacy of effort. 
 
 These symptoms refer to the attention, which acts in a 
 more spontaneous and reflex manner as its control is 
 weakened; the memory is weakened in its power of 
 retaining and recalling ideas. This lessening of inhibi¬ 
 tory power, and mental activity in general, shows the 
 abatement of cerebral energy. It does not always appear 
 to the observer, for the reason that the patient may draw 
 upon the reserved nervous energy, and put forth more 
 effort in the act of controlling his attention, and succeed 
 in doing it. But he is both expending energy more 
 rapidly in so doing, and is conscious of the need of 
 
18 THE MENTAL SYMPTOMS OF FATIGUE. 
 
 increased effort; lie will usually readily confess it on 
 being questioned. This consciousness finally amounts 
 to the very characteristic sense of inadequacy. This 
 symptom of weakened voluntary attention is also an 
 early one, and is very diagnostic. The patient will often 
 complain that he cannot keep his thoughts on his work 
 or business, or has to read over again what he reads, and 
 can not remember it. One patient said 1 ‘ I can not sense 
 it;” and another, “I can not center my mind on what I 
 try to do.” 
 
 A third order of symptoms may now arise, and it is an 
 interesting fact that they grow out of the other two 
 orders, and are their logical consequence; these are 
 morbid introspection, retrospection, and apprehension 
 {worry and hypochondria). 
 
 These symptoms, when manifestly developed, mark a 
 graver degree of fatigue. The emotional tone being low¬ 
 ered, the patient in a state of depression of feeling is 
 prone to “look upon the dark side of things.” Ideas 
 are intensified that are accompanied by painful feelings, 
 which are thus in harmony with the prevailing emotional 
 tone. There being also a lessening of nervous energy in 
 voluntary attention, it cannot inhibit the intensified 
 painful ideas and feelings, and there is consequently 
 worry about the present, past, and future. The vague 
 fear arises of being unable to meet the requirements of 
 the future. The increasing sense of present inability 
 gives intensification to the characteristic sense of inade¬ 
 quacy noted by Beard as being so prominent. 
 
 There is one other set of symptoms to be mentioned as 
 constituting a fourth order. While those previously 
 noted are purely mental, these are partly so, but relate 
 chiefly to alterations that cause peculiar bodily effects, 
 and are often manifest to the observer. These symptoms 
 are : changed organic sensations, physical and mental 
 irritability, and restlessness; diminished sensitive¬ 
 ness, dullness and languor. 
 
 There is apparent irregularity in these changes of 
 
THE MENTAL SYMPTOMS OF FATIGUE. 
 
 19 
 
 bodily feelings and their manifestations—the intensify¬ 
 ing of some and the lessening of others. Arndt 1 says : 
 u It is clear that the increased hyperaesthesia, which a 
 degenerating nerve at first presents, can not last long, 
 and that soon decreased excitability, blnntness, paresis, 
 or whatever we call fatigue or exhaustion, must take its 
 place.” 
 
 There is not alone hyperaesthesia, with the external 
 signs of irritability and restlessness, but there is much 
 diminished sensitiveness. Some cases are altogether of 
 the latter character, and many present both conditions 
 at the same time, in some particulars. It may be a ques¬ 
 tion of the different effects of variations in the toxic 
 waste products. While chemical physiology and pathol¬ 
 ogy do not yet enable us to ascribe sensory and motor 
 disorders definitely to the influence of poisons produced 
 within the organism by its own activity, it cannot be 
 doubted that both the conditions of nervous irritability 
 and those of dullness, languor, and stupor, may be so 
 caused. It is certain that such external manifestations 
 may be caused as the direct expression of defective 
 functional activity in cerebral centres that are the source 
 of the nervous energy which innervates and controls 
 both the somatic and mental mechanisms. The study 
 of physical expression which Darwin raised to the dig¬ 
 nity of a new science, shows that while there is certain 
 voluntary control over it, still the manifestations in the 
 muscular movements of expression, whether occurring 
 in the face or the extremities, have a direct automatic 
 dependence upon interior states of the central nervous 
 system, which are thus externally reflected. The inflow 
 of organic sensations to the senorium has its complement 
 in the constant, regular and subconscious transmission 
 of nerve force from central cells to the muscular peri¬ 
 phery. This accords with Gowers’ statement that every 
 structure of the brain concerned with sensation proper is 
 connected directly or indirectly with a part concerned 
 
 1 Loc. cit. 
 
20 the mental symptoms of fatigue. 
 
 with motion ; and, in regard to the unstable condition of 
 brain cells in disease, when the equilibrium between the 
 discharge of energy and the inhibition of it is disordered, 
 “the discharge may depend on the production of force 
 within being increased in excess of the resistance, or on 
 the resistance being duly lessened.” 
 
 In the common forms of insanity are seen the most 
 pronounced expressions of excessive or diminished cen¬ 
 tral activity, and this applies alike to innervation and 
 inhibition, whether mental or somatic. In the belief of 
 the writer 1 it is possible to detect important variations in 
 the several elements of mental activity in normal fatigue 
 and nervous exhaustion. For example : the letting down 
 of mental power in voluntary control, with the conse¬ 
 quent lessened inhibition of verbal expression of grief 
 and worry, or excitability and aggressiveness. Bancroft 2 
 has made an instructive application of the physiological 
 principles of expression, to the study of facial expression 
 of the emotions in insanity and of expression in posture, 
 etc., as the results of habit in automatic muscular action. 
 His work gives definite value to the clinical use of photog 
 raphy in the physical expression of mental changes. 
 
 All such clinical studies of mental symptoms demon¬ 
 strate the value of precise appreciation of the changes 
 in the elementary mental activities. It is common to 
 observe, in mania, either excessive, uninhibited, mental 
 and motor activity, or the quite normal control of the 
 latter, along with the gravest deficiency of mental inhi¬ 
 bition. Again, there is excessive nerve-muscular activity, 
 or tension in fixed attitudes, in the mental and motor 
 expression of painful emotion in melancholia, and in 
 consequence of lessened inhibitory will power ; and still 
 again, all expression may be abolished in the real mental 
 stupor of melancholia and mania. This abolition may 
 
 1 Pathological Fatigue or Neurasthenia; also the Shattuck lecture; 1891 
 Med. Com. Mass. Med. Soc.— Amer. Jour. Insanity, July and Oct., 1891. 
 
 2 Automatic muscular movements among the insane, Amer. Jour, of 
 Psych., Feb., 1891. 
 
THE MENTAL SYMPTOMS OF FATIGUE. 21 
 
 also be due alone to the fact that, while perception and 
 ideation are quite normal, the power to give expression 
 to them is diminished or lost, either in the failure of the 
 mental function of willing, or of excitability in the 
 motor centres. A man at the McLean Hospital, who was 
 apparently in profound stupor, afterwards said: “ I 
 wanted to answer you, but couldn’t make my jaws go.” 
 A woman who would stand in a fixed position for hours 
 with almost entire loss of muscular movement and ex¬ 
 pressionless face, could respond to kind words only by 
 directing her eyes, and they would fill with tears. When 
 she was well, the next year, she gratefully told what 
 had been said and done to her. The apparent stupor is 
 often mistaken for the real condition. 
 
 These discriminations of the mental processes being 
 once established, they have the highest therapeutic value 
 in their preventive application. Hence the thesis of 
 this paper: the importance of an early appreciation of 
 the mental symptoms of normal fatigue that tends to 
 nervous exhaustion, for they are prodromic of its graver 
 forms. Moreover, the recognition of the significance of 
 changes in the motor and sensory manifestations, in the 
 direction of languor as well as irritability— anaesthesia 
 as well as hyperaesthesia — is of the first importance in 
 the difficult task of managing convalescence from true 
 neurasthenia. The u irritable weakness,” includes the 
 liability to quick exhaustion of the small increments of 
 nervous energy that have been slowly gained, and there¬ 
 with the speedy reduction of sensory, as well as motor 
 power, to the degree of “ bluntness,” as Arndt has stated 
 it. Pathological fatigue, or nervous exhaustion, being 
 shown to be a condition in which there is direct and 
 constant relation between physical disorder and mental 
 symptoms, these should be noted, together with both the 
 increase and the blunting of sensitiveness, in any compre¬ 
 hensive definition of the disease. It may therefore be 
 defined as follows : Neurasthenia is a morbid condition 
 of the nervous system , and its underlying characteris- 
 
22 
 
 THE MENTAL SYMPTOMS OF FATIGUE. 
 
 tics are excessive weakness , and irritability or languor , 
 with mental depression and weakened attention. 
 
 This method of analysis into four orders of symptoms 
 is applicable to all cases of neurasthenic disorder of the 
 physiological activities involved, from the passing over 
 of normal into pathological fatigue, in the simplest 
 forms, to the gravest manifestations of emotional dis¬ 
 turbances, disordered attention, and sensory and motor 
 irritability and languor. The symptoms included in the 
 first three orders are regarded as purely mental; those 
 characterised in the fourth order, while referring to the 
 well-marked development of changes in sensitiveness 
 and activity of bodily functions, imply the necessary 
 association with them of the mental symptoms before 
 noted. These changes of bodily sense and activity may 
 be detected, in the slighter degrees, in the earlier stages 
 of neurasthenia. The value of the practical application 
 of these discriminations in diagnosis may now be illus¬ 
 trated by describing some of the special ways in which 
 certain symptoms must be interpreted. By this method 
 of analysis we may readily estimate the significance of 
 the symptoms of depression of feeling, of weakening of 
 voluntary attention, and of worry. But there are certain 
 more subtle effects of the mixed condition, usually found, 
 of hyperaesthesia and anaesthesia. 
 
 One of the most striking special symptoms which the 
 foregoing considerations point out and may serve to ex¬ 
 plain, is a paradoxical one, but one most commonly pre¬ 
 sented for clinical observation. The sensory function by 
 which the complex normal feelings of fatigue are 
 appreciated, may itself be over-exercised to exhaustion. 
 (There is tire of the power to feel the tire. This condi¬ 
 tion may be called fatigue-anaesthesia , and, beginning 
 with the early stages of pathological fatigue, there is 
 usually some degree of it. Every physician has ex¬ 
 perienced this when, after a night of anxious profes¬ 
 sional work, ,with loss of sleep, he has a day of excit¬ 
 able alertness of mind and body, and there is a sense of 
 
TEE MENTAL SYMPTOMS OF FATIGUE. 23 
 
 nervous strain, with, perhaps, undue mental facility and 
 physical irritability. Many hours sleep may be gained 
 in the following night, but instead of feeling refreshed 
 he has a sense of malaise , languor and fatigue. The 
 real fatigue was greater the day before, but he could not 
 feel it as such. It is not until the second day after the 
 excessive effort that he has recovered his exhausted 
 power to feel the fatigue. In a lesser degree this fatigue- 
 anaesthesia becomes a constant accompaniment of the 
 neurasthenic condition. Over-worked women, profes¬ 
 sional and business men, “ work on their nerves,” and 
 say they “ don’t feel tired, and nothing is the matter.” 
 They “feel better” when actively exercised in their 
 customary labors. This condition comes on insidiously 
 and is a most dangerous onej The patient is neuras¬ 
 thenic before anybody suspects it. With the impair¬ 
 ment of the natural fatigue-sense the mental effect is that 
 he will not believe even his physician’s diagnosis of 
 “fatigue.” He is, therefore, prone to look for some 
 other reason for his sense of ill-being and inefficiency ; 
 and finds, in retrospection, cause for self-reproach and 
 hopelessness in the future. 
 
 Fatigue - anaesthesia manifests itself in connection 
 with another special symptom peculiar to conditions of 
 “fatigue,” that of “morning tire,” sometimes called 
 “morning misery.” Extreme examples of this are seen 
 in the victims of dissipation. In ordinary cases of 
 pathological fatigue it is a persistent symptom; the 
 patient is likely to awake in the early morning unre¬ 
 freshed by a fair amount of sleep, and often in the depths 
 of depression. The physical signs of exhaustion are then 
 more manifest. These symptoms represent the truth as 
 to his neurasthenic condition. After breakfast he feels 
 better, and by the middle of the day the stimulation of 
 the daily interests and press of business has apparently 
 restored his good feeling. At the close of the day he is 
 comfortable and cheerful, laughs at his morning fears, 
 and is prone to over-do himself in recreation or evening 
 work. That day’s experience is regularly repeated. 
 
24 
 
 TEE MENTAL SYMPTOMS OF FATIGUE. 
 
 Each night he rests enough to recover some of the feel¬ 
 ings that attend upon “ fatigue,” but he often does not 
 recognise it in the absence of the true fatigue-sense. A 
 still further blunting of this sense is caused by the ill- 
 timed stimulation of unwisely continued effort. Along 
 with the restlessness of his “ irritable weakness,” there 
 is a fictitious sense of well-being because of the tempor¬ 
 ary abolition of the sense of ill-being, as in mild intoxi¬ 
 cation by alcohol. 
 
 In the management of convalescence from neurasthenia, 
 or of cases that would get well if they could be man¬ 
 aged, there is nothing more discouraging than the succes¬ 
 sion of relapses that they undergo. Such patients, having 
 been subjected to rest treatment, may be fat enough and 
 maintain a fair degree of comfort when effort is kept 
 within the limits of pathological fatigue. They complain 
 of tire and various discomforts upon a little effort, which 
 must be made in order to gain by physiological use the 
 strength to make it. It seems a never-ending process 
 some patients cannot abide its slowness, and make effort 
 too soon ; others resist great persuasion to make enough. 
 But some event may occur that excites desire or a sense 
 of duty. The undue quickness of response to the stimu¬ 
 lation of interest and attention is to be recognised as an 
 evidence of irritable weakness. The apparent ease and 
 unwonted zest of the effort is not a manifestation of real 
 power; it means that there is a speedy blunting of the 
 sense of fatigue. The reaction of exhaustion and mental 
 misery that follows shows the real weakness and the need 
 of unfailing patience and discretion. Most patients of 
 this class have to be taught how to recognise the mental 
 and physical signs of fatigue peculiar to themselves, 
 other than the normal feeling of it. They must also be 
 taught that some degree of fatigue thus manifested must 
 be regularly incurred as wholesome tire. But both 
 patient and physician must be guided alone by indi¬ 
 vidual experience and judgment as to the amount of 
 effort. Feeling is often a misleading guide for doing or 
 not doing. 
 
THE MENTAL SYMPTOMS OF FATIGUE. 
 
 25 
 
 Many neurasthenic people are plied with recreation 
 to “ distract the attention,” and go on journeys in 
 search of health, when it is not stimulation, mental or 
 physical, that is needed, but rest. The physician may 
 save many a patient from such a final strain, that would 
 precipitate a break-down, by recognising the fact that 
 his apparent ability to do things without fatigue, when 
 the mental signs of it are present, is the strongest indi¬ 
 cation that he has reached a dangerous degree of nervous 
 exhaustion, marked so plainly by loss of the fatigue-sense. 
 In such cases, after a course of rest treatment, which 
 must often be more or less modified, exercise becomes 
 most important, in the form of gentle bodily effort and 
 mental stimulation by recreation in gradually increased 
 amount. The guide to the limitation of exercise is to be 
 found in its effects, such as the slight return of restless¬ 
 ness and insomnia at night, and the mental and bodily 
 discomfort liable to appear on the following morning. 
 Exercise may be pressed to the extent of not causing 
 these effects ; it promotes nutrition, and excretion of 
 waste products, the free action of the skin, etc. 
 
 The physician will look to the therapeutics of tonics 
 and nutrition, with careful attention to all the forms of 
 elimination. But while he is doing this, the successful 
 treatment of neurasthenia means the careful recognition 
 of all its signs. The earliest indications for diagnosis, 
 and the clearest for treatment—and often the only ones 
 —are the mental symptoms. It is the conditions of 
 fatigue that are to be treated, and the study of the 
 working of the fatigue-sense affords the safest and surest 
 guide, although its signs are so often negative. A cor¬ 
 rect and fine appreciation of what the mind can do 
 enters into our commonest knowledge and experience, 
 and we use the most familiar words to describe its oper¬ 
 ations. This paper has been written with the hope that 
 it may be a help to the systematic observation of some of 
 the commonest and most valuable of clinical indications, 
 both for prevention and cure. 
 

 
 
 
 
 
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