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THE HUMAN MACHINE 
 
 AND 
 
 INDUSTRIAL EFFICIENCY 
 
THE HITMAN MACHINE 
 
 AND 
 
 INDUSTRIAL EFFICIENCY 
 
 BY 
 FREDERIC S. LEE, Ph.D., LL.D. 
 
 Daltnn Professor of Physiology in Columbia University; President of the 
 
 American Physiological Society; Consulting Physiologist to the U.S. 
 
 Public Health Service; Chairman of the Sub-Committee on 
 
 Fatigue in Industrial Pursuits of the Xational Research 
 
 Council; Executive Secretary of the Divisional 
 
 Committee on Industrial Fatigue under 
 
 the Advisory Commission of the 
 
 Council of National Defense 
 
 WI Til ILL US TRA TIOXS 
 
 LOXGM A N S, G R E E~N AND C O 
 
 FOURTH AVENUE & 30th STREET, NEW YORK 
 39 PATERNOSTER ROW. LONDON 
 
 BOMBAY, CALCUTTA, AND MADRAS 
 
 1918 
 
Copyright, 1918 
 By FREDERIC S. LEE 
 
 All Rights Reserved 
 
 PRESS OF 
 BRAUNWORTH & CO- 
 BOOK MANUFACTURERS 
 BROOKLYN, N. V. 
 
PREFACE 
 
 Most of the substance of this little book con- 
 stituted the two Cutter Lectures on Preventive 
 Medicine and Hygiene, which were given at the 
 Harvard Medical School, April 25 and 26, 1918, 
 under the title " Industrial Effieicnc}' and the 
 War." Many of the facts here presented relate 
 to war industries, but they are none the less 
 pertinent as illustrating the principles enunciated; 
 and even if interest in the facts dies out, the prin- 
 ciples, it is hoped, will survive and receive atten- 
 tion long after the war has ended. I believe 
 fully that any activity in which the human body 
 plays so large a part as it does in industry must be 
 organized on a physiological basis before the high- 
 est degree of efficiency can be secured. In the 
 field of human activity here discussed a science 
 of industrial physiology must come into being, a 
 science of the human machine in industry, and 
 this must be developed largely within industrial 
 establishments themselves. They constitute the 
 laboratories in which much of the observation and 
 experiment of the future must be made. If I can 
 help to make this thought accepted by others than 
 
vi PREFACE 
 
 physiologists and especially by industrial leaders, 
 I shall be gratified. 
 
 In preparing this summary of our present knowl- 
 edge I am under many obligations to my col- 
 leagues in the U. S. Public Health Service and the 
 Committees on Industrial Fatigue. Their names 
 will be found at the beginning of the Bibliography 
 printed at the end of the volume. The numbers 
 in the text refer to the Bibliography. 
 
 Frederic S. Lee. 
 Columbia University, 
 June 1, 1918. 
 
CONTENTS 
 
 I. Introduction 
 
 1 
 
 II. The Qualifications of AVorkers ... 5 
 
 III. Output and Fatigue 10 
 
 IV. Secondary Sources of Fatigue . . .19 
 V. Resting Periods 24 
 
 VI. The Length of the Working Day ... 29 
 VII. Capacity and the Self-limitation of Output 39 
 VIII. The Maintenance of Working Power. Over- 
 time 43 
 
 IX. The Labor Turnover 49 
 
 X. The Industrial Efficiency of Women Com- 
 pared with Men 53 
 
 XL Night Work in Comparison with Day Work 61 
 
 XII. Industrial Accidents 73 
 
 XIII. Industrial Medicine. Welfare Work . . 79 
 
 XIV. Food 84 
 
 XV. Scientific Management 90 
 
 XVI. The Physiological Organization of Work . 96 
 
 XVII. Summary 100 
 
 Bibliography 105 
 
 Index 115 
 
 vii 
 
THE HUMAN MACHINE 
 
 INTRODUCTION 
 
 In the modern factory the science of machinery 
 is developed to its highest point. In the selection, 
 construction, and use of the machine nothing 
 is left to chance. Its type is selected in accord- 
 ance with its exact fitness for the work demanded 
 of it. It is constructed of appropriate materials 
 and is so designed as to avoid lost motion and the 
 waste of energy involved and to allow the highest 
 possible proportion of the total energy that is 
 transformed to perforin the work required. It is 
 kept clean, unnecessary friction is avoided, and 
 every care is taken that its bearings shall not 
 become corroded, rusted, or worn beyond repair. 
 When in action it is run at a speed for which it is 
 planned, it is not overloaded, and not overheated; 
 the conditions under which it can work with the 
 greatest efficiency have been carefully studied; 
 and every effort is made to maintain these condi- 
 tions and secure the largest possible output with- 
 
2 THE HUMAN MACHINE 
 
 out injury or unnecessary deterioration of the 
 machine itself. And the machine, it should be 
 added, responds to all the care expended on its 
 welfare and proves by what it does the value of 
 the efforts made in its behalf. 
 
 But there is another element in factory equip- 
 ment which must direct, make useful and supple- 
 ment the machinery, and this is the human ele- 
 ment. The term " labor-saving machinery " is 
 misleading; for, while the modern factory machine 
 does indeed save labor in some degree, it gives 
 labor more opportunities, directs it into new chan- 
 nels, confines it to more specialized operations, and 
 makes it more necessary than ever to industrial 
 advance. It is pertinent to our present purpose 
 to regard this human element, the combined body 
 and mind of the worker, as itself a machine. 
 There is nothing derogatory to the worker in this 
 conception; it is the customary conception of 
 physiological science, which has learned to respect 
 living substance above all other created things and 
 yet finds it most helpful to regard every living body 
 as a mechanism working according to the funda- 
 mental laws of all mechanisms, but with its own 
 specific ways of acting that characterize living in 
 contrast to non-living substance. No other fac- 
 tory mechanism approaches this human machine 
 in its intricacy, the perfection of the correlation 
 of its working parts, its combination of delicacy 
 
INTRODUCTION 3 
 
 and strength, and its adaptability to the work 
 required of it. None is so essential to industry. 
 
 Nevertheless, the present ways of handling the 
 human machine are empirical and crude. Experi- 
 ence has taught most industrial managers what 
 they believe to be the proper ways of dealing with 
 the workers, and experience is conceived to be the 
 best guide. The thought that the worker is a 
 physiological mechanism and should be treated 
 as such, that the problem of the worker is a physio- 
 logical problem, is regarded as academic, fit for 
 the laboratory, but not " practical " enough for 
 the factory. That word " practical " is one of 
 the most alluring, most dangerous and most mis- 
 used words in the English tongue. Crimes un- 
 numbered have been committed in its name. It is 
 true that the science of the human machine as 
 employed in industrial work has not yet been de- 
 veloped so far as that of non-living machinery, but 
 the utilization of the science has not kept pace 
 with its advance, and though here and there a 
 factory management stands out as being fully 
 alive to the desirability of organizing its work on a 
 really scientific basis, to the average manager 
 this is yet to be proved. 
 
 The war is making unprecedented demands on 
 industry. It is now generally recognized that 
 toward the winning of the war industrial effort 
 must contribute as much as military effort, and 
 
4 THE HUMAN MACHINE 
 
 just as military activity is everywhere seeking as 
 never before the aid of science, so the indus- 
 trial system, if it would respond loyally to the 
 call upon it, cannot continue to rely upon its tra- 
 ditional methods, but should utilize whatever help 
 science can give. That physiology can give much 
 to industry has been demonstrated during the past 
 three years by investigations that have been car- 
 ried on, in both America (1) and England (2), 
 especially in munition factories, and it is chiefly 
 to some of the results of these investigations that 
 the present pages are to be devoted. 
 
 In order that the highest degree of efficiency 
 may be secured in industrial work, it would seem 
 obvious that certain fundamental conditions should 
 be fulfilled. These include the following : 
 
 1. Workers should be qualified for the work 
 that they are to do. 
 
 2. Workers should produce a daily output in ac- 
 cordance with their individual capacities for work. 
 
 3. Workers should maintain their working power 
 from day to day and from week to week. 
 
 4. Workers, once they are proved competent, 
 should be retained. 
 
 These conditions seem axiomatic, and yet they 
 are rarely fulfilled. In the following pages I pro- 
 pose to consider them, as well as certain other 
 topics relating to the human machine in industry. 
 
II 
 
 THE QUALIFICATIONS OF WORKERS 
 
 Modern industry makes an infinite variety of 
 demands on the physical and mental qualifica- 
 tions of its workers. The number of different 
 operations that are required in any branch of a 
 single manufacture are little known to the lay- 
 man. The simple assembling of the various parts 
 of the engine of an automobile consists of some 
 two hundred distinct manipulations, and with 
 the modern division of labor these can most ad- 
 vantageously be assigned to at least an equal 
 number of operatives. Before the assembling 
 come the thousands of tasks involved in the man- 
 ufacture of the different parts. It is reported of 
 one large factory that in the process of manufac- 
 turing its goods more than a half million different 
 acts must be performed. Wherever these varied 
 acts are performed by machinery the use of ma- 
 chines not properly adapted to the work would 
 obviously be inexcusable. The time and thought 
 that are given to the invention and perfection of 
 machines and the determination of the ways 
 
 5 
 
6 THE HUMAN MACHINE 
 
 by which they can be handled most efficiently are 
 a measure of the demands for mechanical fitness 
 that are made by the industrial manager. 
 
 To the qualifications of the human machine, 
 however, the manager usually gives little prelim- 
 inary attention. The custom frequently is to hire 
 with but little previous examination whoever ap- 
 plies for a position, assign him to a particular task, 
 and learn then what he is capable of — a method 
 that imposes upon the quantity and quality of the 
 manufactured product the possibility of his failure. 
 The cost of this failure manifested in misused time 
 and spoiled work would be saved if the worker, 
 before being given valuable raw material, would 
 be made to prove his qualifications by proper 
 tests. 
 
 From various directions, especially from the 
 psychological laboratories, come suggestions of 
 methods for determining special vocational fitness. 
 The work of Miinsterberg (3) is well known, in 
 which he describes simple tests for memory, 
 attention,' intelligence, exactitude and rapidity 
 in the case of telephone operators, and attention 
 tests with motormen in street railway service. It 
 must be confessed, however, that the whole matter 
 of ascertaining occupational aptitudes is still in its 
 infancy, and the laboratories and factories are 
 still far removed from really adequate methods. 
 
QUALIFICATIONS OF WORKERS 7 
 
 There are here needed both analyses of the tasks 
 for the purpose of learning what human qualifica- 
 tions they require, and adequate tests to determine 
 whether individuals possess the required quali- 
 fications. Hollingworth (4), in a recent survey 
 of the topic of vocational psychology, while recog- 
 nizing that " there are some twenty types of work 
 for which tests have already been proposed, rec- 
 ommended, and more or less tentatively tried," 
 concludes that " the reliable vocational psycho- 
 graph, which proceeds by means of a careful pre- 
 liminary analysis of the qualities required in the 
 given work, and uses specially adapted tests with 
 reliable norms for their evaluation, is not yet 
 available for any single occupation. The pre- 
 liminary analyses, so far made, whether by em- 
 ployer, psychologist, or engineer, give us little 
 guidance, and until such guidance is forthcoming 
 the special adaptation of tests and the accumula- 
 tion of norms and standards cannot make much 
 practical progress." Here is needed above all 
 else the aid of the laboratories, both within and 
 without industrial establishments, and in per- 
 forming the task the two sciences of physiology 
 and psychology must work hand in hand. 
 
 But notwithstanding the present lack, the war 
 has brought into prominence certain methods that 
 promise to be valuable. The general intelligence 
 
8 THE HUMAN MACHINE 
 
 tests which our army has adopted are affording 
 data for the mental classification of our soldiers. 
 Our aviation service, by means of carefully planned 
 and conducted physiological and psychological ex- 
 periments, is determining standards by means of 
 which the capabilities of our aviators at different 
 altitudes and for different varieties of service will 
 become known. Lovett and Martin's (5) spring- 
 balance muscle test, originally designed for the 
 determination of the degree of recovery in muscles 
 paralyzed in poliomyelitis, has, during the past ten 
 months, been used with excellent results in our 
 munition factories. This consists in measuring, 
 by a very simple and quickly applied method, the 
 strength of certain selected groups of muscles and 
 computing from the figures thus obtained the total 
 strength of the individual. Individuals are then 
 classified into four groups: the exceptionally 
 strong, the strong, the moderately strong, and the 
 weak. The use of this test by Professor Martin 
 under the Public Health Service (1) has disclosed 
 the fact that different specific industrial operations 
 have different specific standards of strength, as is 
 illustrated by the following table: 
 
 Operation Average 
 
 _ _ Strength 
 
 MEN et Pounds 
 
 Rivet dipping 4g7Q 
 
 Rivet trucking 4g30 
 
QUALIFICATIONS OF WORKERS 9 
 
 _. Average 
 
 Operation _ 
 
 Strength 
 
 Men in Pounds 
 
 Hot forging 4370 
 
 Rivet shoveling 4260 
 
 Coal passing 4230 
 
 Capstan lathe (day shift) 4180 
 
 Planish seat 3930 
 
 Foremen 3770 
 
 Powder loading 3700 
 
 Women 
 
 Drilling flash holes 2370 
 
 Mill percussion flash 1780 
 
 Welsbach foot press 1640 
 
 Drilling diagonal holes 1630 
 
 It is obvious that if the strength of any worker 
 consistently falls much below the standard for the 
 task to which he has been assigned, he is under- 
 taking work for which he is not physically fitted; 
 and if his strength is markedly greater than that of 
 his task he is not economically placed. These dis- 
 advantages in assigning the worker to the task 
 that is unsuited to his strength could be avoided 
 if the spring-balance test should come into general 
 industrial use. 
 
Ill 
 
 OUTPUT AND FATIGUE 
 
 A careful study of the hourly and daily output 
 of individual workers in specific tasks throws 
 much light upon the general problem of the human 
 machine in industry and its efficiency (6). Such a 
 study is being made in some of our munition fac- 
 tories by the U. S. Public Health Service working 
 in cooperation with the Committees on Industrial 
 Fatigue under the National Research Council and 
 the Advisory Commission of the Council of Na- 
 tional Defense (1). 
 
 The manufacture of fuses for explosive shells 
 offers excellent opportunities for the study. In 
 the making of a single fuse several hundred sepa- 
 rate operations are required, and these are usually 
 assigned to at least as many different workers. 
 The work is repetitive; each operation is compara- 
 tively brief and simple and is repeated successively 
 throughout the whole working period as the con- 
 stant train of similar parts passes before the 
 worker, who may thus perform his task several 
 thousand times between morning and night. In 
 
 10 
 
OUTPUT AND FATIGUE 11 
 
 most of the operations a non-living and a human 
 machine combine. An automatic recorder or an 
 observer may record the number of times the 
 operation is performed, or the number of pieces 
 completed may either be counted or be calcu- 
 lated from the weight of the product. A conveni- 
 ent unit of time for the measurements is one hour. 
 It is thus easy to obtain the curve of output 
 throughout the working period. 
 
 This curve is found to vary with the character 
 of the work. Of operations that require careful 
 attention and exact muscular coordination, that 
 of applying lacquer to certain screw-holes of the 
 fuse is typical. Such a curve showing the hourly 
 distribution of the work of women during a ten- 
 hour period of the day shift, is reproduced in Fig. 1 . 
 The work began at 7 o'clock in the morning and 
 continued until 12 o'clock noon; there was then a 
 break of one hour for luncheon and recreation; 
 the afternoon work began at 1 and ended at 6 
 o'clock. The average number of pieces handled 
 by each person during the day was 6250, of which 
 3250 were finished in the forenoon and 3000 in the 
 afternoon. The output, which began well, in- 
 creased during the first two hours of the forenoon 
 spell and bj r 9 o'clock had reached a maximum 11 
 per cent above the product of the first hour; it 
 then decreased at almost a constant rate through- 
 
12 
 
 THE HUMAN MACHINE 
 
 out the remainder of the spell and by noon had 
 fallen 6 per cent below the record for the first hour 
 and 17 per cent below the maximum. The curve 
 
 ) ' i ' i ' i 
 
 LUNCH 
 
 I ' i ' I ' i ' I 
 
 10 11 12 1 
 
 6 
 
 Fig. 1. — Curve of output in painting screw-holes with lacquer, 
 an industrial operation that requires careful attention and 
 exact muscular coordination. The height of each point in 
 the curve above the base line represents the output of 
 the corresponding hour. Women workers; day work; 10- 
 hour shift. (By courtesy of the U. S. Public Health Ser- 
 vice.) 
 
 of the afternoon spell shows a general form similar 
 to that of the morning but with quantitative dif- 
 ferences; the first hour's production is greater than 
 
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OUTPUT AND FATIGUE 13 
 
 that of the last hour of the morning; but the rise 
 to the maximum is less and the subsequent fall 
 much greater. The output of the final hour in- 
 deed is 32 per cent less than that of the maximum 
 for the day, and the total output of the afternoon 
 is 4 per cent less than that of the forenoon. 
 
 The interpretation of such a curve on a physio- 
 logical basis is aided by the consideration of cer- 
 tain other physiological phenomena. The curve 
 of each spell is not unlike the curve of output of a 
 single isolated muscle contracting upon being arti- 
 ficially stimulated at regular intervals and lifting 
 a given load (Fig. 2). In the muscle curve the 
 preliminary rise, called the " treppe " or " stair- 
 case," represents an improvement in working 
 power due to chemical and physical changes within 
 the muscle ; the gradual fall represents the diminu- 
 tion of working power involved in fatigue, which 
 is due in turn to chemical and physical changes 
 within the muscle. These events within the mus- 
 cle are purely objective phenomena; in the human 
 machine there are added to the objective muscular 
 contractions the subjective phenomena of the 
 nervous system, which complicates the physiologi- 
 cal situation enormously. Nevertheless the ap- 
 parent similarity between the two curves suggests, 
 although it does not make certain, a similar funda- 
 mental interpretation. The rise in the curve of 
 
14 THE HUMAN MACHINE 
 
 output of the human machine is commonly called 
 the " practice effect.'' It probably represents 
 mainly a real increase in working power, resulting 
 from improved focussing of attention and better 
 neuromuscular coordination, and, were our knowl- 
 edge Sufficiently complete, it probably could be cor- 
 related with chemical and physical changes within 
 the body. The fall in the human curve probably 
 consists in considerable part of an actual decrease 
 of working power, caused by fatigue, although a 
 voluntary, wilful lessening of work may enter into 
 it. The increased output immediately after lunch- 
 eon is the expression of the increase in working 
 power that results from food and rest. The greater 
 final fall in the afternoon, as compared with the 
 morning, spell probably represents in great part 
 the cumulative fatigue of the day. 
 
 Certain tests more objective than that of output 
 have recently demonstrated also that fatigue re- 
 sults from the day's work. The spring-balance 
 muscle test (5) applied at the beginning and the end 
 of the day's labor in some of our munition factories 
 shows that the work of the more strenuous opera- 
 tions results usually in a diminution of the total 
 strength of all the workers; in operations requiring 
 moderate exertion only the weaker workers show 
 the effect. A day in which the worker for any 
 intrinsic reason possesses less strength than usual 
 
OUTPUT AND FATIGUE 15 
 
 is apt to be followed by a day showing more than 
 the usual fatigue; and a day of severe fatigue by 
 one of lessened strength. On days when the 
 strength test shows high figures output tends also 
 to be high, and vice versa. 
 
 Ryan's (7) vascular skin reaction test consists 
 in making, with a suitable blunt instrument, a 
 stroke on the skin of the forearm and noting by 
 means of a stop-watch the time that elapses 
 between the moment of the stimulation and the 
 moment at which the white streak thus caused 
 begins to fade. This time is shorter in the 
 fatigued person. The test is applied several times 
 daily. The curve of duration of the streak falls 
 during the forenoon indicating fatigue, rises some- 
 what during the luncheon hour indicating restora- 
 tion, and falls again to a minimum during the 
 afternoon. If the subject spends the half day 
 resting instead of working, the fatigue fall of the 
 curve does not occur and a rise may result. Pro- 
 fessor Ryan is now making, under the Public 
 Health Service, an extensive experimental study 
 of the applicability of this test to the conditions of 
 industrial work. 
 
 Kent (8) has demonstrated a certain degree of 
 lessened acuity of both sight and hearing as the 
 result of the day's work in the factory, but how 
 general this is cannot now be said. 
 
16 THE HUMAN MACHINE 
 
 Hastings (1), in a series of observations extend- 
 ing over several months under the Public Health 
 Service, finds that the urine of day workers in 
 munition factories possesses a higher degree of 
 concentration of hydrogen ions in the evening as 
 compared with the morning. That this sign of 
 acidosis is also a sign of fatigue is indicated by 
 control observations on resting subjects, in whom 
 there is a slight decrease in the same ions during 
 the day. 
 
 All these recent observations agree in demon- 
 strating by objective methods that fatigue is 
 present at the end of the day's labor and they 
 justify the assumption that the fall in the curve 
 of output is a sign, in part at least, of fatigue. 
 Additional methods of revealing such fatigue are, 
 however, desired. The difficulties of applying any 
 method to industrial workers, who are unac- 
 quainted with scientific experimentation and many 
 of whom are impatient of devoting their time to 
 mysteries of the meaning of which they are igno- 
 rant, are much greater than with trained labora- 
 tory subjects. 
 
 Not all curves of daily output are as simple as 
 that presented. In operations that require con- 
 siderable muscular strength a curve (Fig. 3) is 
 sometimes seen in which for each spell there 
 appears no practice effect, but a continuous fall, 
 
OUTPUT AND FATIGUE 17 
 
 LUNCH 
 
 7 8 9 10 11 12 12 3 4 5 
 Fig. 3. — Curve of output in polishing metal by hand, an indus- 
 trial operation that requires considerable muscular strength. 
 The height of each point in the curve above the base lino 
 represents the output of the corresponding hour. Men 
 workers; day work; 10-hour shift. (By courtesy of the 
 U. S. Public Health Service.) 
 
18 THE HUMAN MACHINE 
 
 often broken, however, in the latter half of the 
 spell by a brief temporary rise, indicating a spurt 
 on the part of the worker. The fall is often very 
 marked and the significance of the spurt is not 
 clear. Where work is monotonous and inter- 
 rupted by frequent rests, outputs have been 
 observed the curves of which for each spell are 
 undulating, but show little, if any, distinct fatigue 
 fall. Many other forms of curves have been 
 seen, but sufficient data have not yet been accumu- 
 lated to allow a classification into types. 
 
 The very frequent indication of fatigue in a 
 study of output and the recognition that fatigue 
 is an enemy to high production bring fatigue into 
 great prominence in any study of industrial effi- 
 ciency (9). A certain degree of fatigue is the ex- 
 pected result of a day's work; it is normal; and 
 when it is not revealed in the output it is question- 
 able whether the individual is approximating his 
 capacity as nearly as he should approach it. 
 When, however, the curve of output does show a 
 falling-off it is not necessarily a sign that fatigue 
 has become excessive and it does not necessarily 
 convey a warning that the output should be cut 
 down. It is always allowable to consider whether 
 output may not even be increased by altering the 
 conditions of the work. 
 
IV 
 SECONDARY SOURCES OF FATIGUE 
 
 If a search after ways of eliminating fatigue 
 is to be thorough the individual worker should be 
 carefully observed and the conditions of his task 
 should be carefully analyzed. Such an analysis 
 reveals that there are primary and secondary 
 sources of fatigue. The primary source of fatigue 
 lies in the performance of the essential part of the 
 operation itself involving the transformation of a 
 definite amount of energy. This is the irreducible 
 minimum, stripped of all non-essential accompani- 
 ments. It is sometimes possible, as will be shown 
 later, to measure with a fair degree of accuracy the 
 amount of work performed in this essential part 
 of the operation and thus determine the primary 
 fatiguing capacity of the task. This source of 
 fatigue is unavoidable. 
 
 But it is different with the secondary sources of 
 fatigue. These comprise certain actions and bodily 
 positions which accompany but are not needed 
 in performing the task, together with certain other 
 environmental conditions under which the task is 
 performed. Gilbreth (\0) found that with the 
 
 19 
 
20 THE HUMAN MACHINE 
 
 customary way of laying bricks eighteen motions 
 were employed in laying a single brick, but eleven 
 of these could be omitted altogether, and some of 
 the others could be combined, so that the required 
 motions were reduced to one and three-quarters. 
 The material and the tools which the worker uses 
 are often placed at a distance from his hands and 
 not where he can get them with the least possible 
 movement and expenditure of energy. A worker 
 is often forced to stand at his work, when he might 
 more economically sit. Stools are less efficient as 
 labor savers than are chairs; and a chair should 
 have an adjustable back. A high chair should be 
 provided with an adjustable foot rest, especially 
 with women workers. The rate of a factory 
 machine run by power is usually set more or less 
 arbitrarily and the worker is expected to conform 
 to it, although his own neuromuscular rhythm, the 
 rhythm at which he can do his best work, may be 
 slower. Such conditions of work, while they may 
 appear trivial, nevertheless, may cause needless 
 muscular contractions, needless or unwise expen- 
 diture of energy, and thus may add to the fatigue 
 of the worker. Their avoidance is usually a very 
 simple matter (11). 
 
 Other environmental contributing causes of 
 fatigue relate to illumination, ventilation, food, 
 and various sanitary conditions. 
 
SECONDARY SOURCES OF FATIGUE 21 
 
 Here may be mentioned lack of sufficient illumi- 
 nation, misplaced artificial lights, and location 
 of workers and machines so as not to secure 
 the full benefit of window lighting. Even when 
 general illumination is sufficient a glare of light 
 on the work bench or the material may be 
 harmful. 
 
 Lack of proper ventilation (12) is a frequent 
 condition of unnecessary fatigue. The investiga- 
 tors of the Public Health Service (1) have found 
 that the different members of a group of workers 
 on the same job frequently show similar varia- 
 tions in total strength; and the same is shown by 
 different groups of workers who have different 
 jobs but similar external environments. Such 
 facts indicate that strength is affected by exter- 
 nal influences, and the investigators have found 
 that air temperatures of 85° F., or above, espe- 
 cially when maintained for several days, reduce 
 the worker's strength. My colleague, Dr. Scott, 
 and I (13) have shown by a series of experiments 
 on animals that the heat and humidity of the 
 air diminish muscular power. At an average 
 temperature of 69° F. (21° C.) and an average 
 humidity of 52 per cent the total amount of work 
 that could be performed by certain selected mus- 
 cles before they were exhausted was regarded as 
 100 per cent; after the animals had been exposed 
 
22 THE HUMAN MACHINE 
 
 for six hours to an " intermediate " condition of 
 temperature of 75° F. (24° C.) and humidity 
 of 70 per cent the total work possible fell to 
 85 per cent, and after a " high " condition of 
 91° F. (33° C.) and humidity of 90 per cent, the 
 work dropped to 76 per cent. Not only a hot and 
 humid but a still atmosphere is bad; the air of 
 the working place should be reasonably cool, 
 moderately dry, and kept in motion (14). An ab- 
 solutely constant temperature is not so beneficial 
 as one that is varied. The enervating effect of a 
 high temperature may be much avoided by the 
 use of electric fans. A purely artificial system 
 of ventilation is probably never so efficient as one 
 that makes use also of open windows, with their 
 possibilities of playing upon the skin a variable air 
 supply. Variety is one of the essentials of good 
 ventilation. 
 
 Lack of adequate and properly selected and 
 cooked food is a frequent obstacle to high pro- 
 ductivity. (See page 84.) The same may be 
 said of a lack of adequate bathing and toilet 
 facilities. The time has gone by when these aids 
 to cleanliness are to be considered as mere 
 needless luxuries. If the human machine is to 
 be in its best working condition it must be kept 
 clean within and without. 
 
SECONDARY SOURCES OF FATIGUE 23 
 
 While these causes of fatigue are secondary they 
 are none the less real and their elimination con- 
 duces to the greater productivity of the human 
 machine. 
 
V 
 
 RESTING PERIODS 
 
 The obvious physiological antidote to fatigue 
 is rest. The effect of a resting period in a single 
 muscle is strikingly shown by an easily performed 
 laboratory experiment on an animal (Fig. 4). 
 If the muscle be stimulated by a series of gentle 
 electric shocks a record of its contractions can 
 readily be made on a revolving drum. Such 
 a record shows, after a few minutes, a diminution 
 in the extent of the contractions because of 
 fatigue. If then the stimuli cease, and a rest 
 is allowed, the working power of the muscle is 
 largely restored. The blood has washed out of 
 the tissue the accumulated toxic fatigue sub- 
 stances, has brought to the wearied cells food and 
 oxygen, and they are prepared again to undertake 
 their labor. In such an experiment, which can 
 be performed painlessly upon a frog, the condi- 
 tions of work are purposely exaggerated, but the 
 principle of the value of resting periods thus illus- 
 trated is applicable directly to industrial labor. 
 
 In industry the resting period is a necessity, and 
 24 
 
RESTING PERIODS 25 
 
 one of the first questions that press for consider- 
 ation is that of the most advantageous length and 
 distribution of resting in relation to working peri- 
 ods. Mankind long ago decided that the working 
 day should be cut into halves and that one hour of 
 rest with luncheon should separate the two spells; 
 and further that school children ought to have 
 additional recess periods. Industry accepts the 
 luncheon period, often shortening it, however, 
 by one-quarter, one-half, and sometimes two- 
 thirds of the conventional horn'; but is loath to 
 believe that additional resting periods may be 
 advantageous. The value of the luncheon period 
 in increasing output is sufficiently demonstrated 
 by such graphic evidence as is furnished by Figs. 
 1 and 2, where there was a pronounced rise in the 
 curve of production following the noon rest. As 
 to the length of the luncheon period both experi- 
 ence and physiology plainly teach, I believe, that 
 it should not be less than one hour whatever the 
 length of the working period. No one can long 
 continue to be proof against the direful effects of 
 the quick lunch. 
 
 As to additional resting periods indisputable 
 evidence also has been accumulated of their real 
 value to the employer by increasing output. The 
 first exact studies in this direction were those of 
 Taylor (15) twenty years ago, who measured with 
 
26 THE HUMAN MACHINE 
 
 a stop-watch the time during which a worker in a 
 given simple operation was actually working. 
 Taylor's subject of observation, Schmidt, bids fair 
 to be one of those immortal characters which we 
 sometimes meet in scientific literature, immor- 
 talized because of their submission to experimen- 
 tation that makes possible important scientific 
 advance. It was Schmidt's task to pick from a 
 pile of pig iron on the ground a single pig, weighing 
 about 92 pounds, carry this up an inclined plank 
 and drop it upon a railway car, and this task was 
 repeated all day long. Though simple it was a 
 heavy muscular task, and Schmidt usually han- 
 dled about 12.5 tons of iron in the day. Taylor 
 found, by " experiments " he says, although the 
 nature of the experiments is not fully revealed, 
 that in such work a first-class laborer should be 
 under load only 42 per cent of the day, and free 
 from load during the remainder of the time. With 
 the usual manner of working there was no assur- 
 ance that this proportion was adhered to. A 
 change was then introduced: Schmidt was put 
 under strict orders; his movements were timed by a 
 stop-watch; and after loading ten to twenty pigs 
 he was required to rest for a definite time. With 
 such a system of alternating work and rest periods 
 it was found that he was able to load in one day, 
 and to continue to load day after day without 
 
RESTING PERIODS 27 
 
 detriment, not 12.5 tons as before, but 47 tons, an 
 increase of 266 per cent. 
 
 The investigators of the U. S. Public Health 
 Service (1) have introduced into certain operations 
 in one of our munition factories a recess of ten 
 minutes in each spell of the ten-hour day. The 
 observations are not yet completed, but they 
 show at the present date almost invariably an 
 increase in the output. For example, in a solder- 
 ing operation three successive periods of two or 
 three weeks each after the introduction of the 
 recess periods revealed an average increase in pro- 
 duction of 3, 17 and 26 per cent respectively. In 
 another factory, engaged in the manufacture of 
 automobiles, where an eight-hour day prevails and 
 working up to capacity is regularly expected, a ten- 
 minute recess, although followed by a temporary 
 acceleration, resulted usually in a slight fall in the 
 average total output of the shift. The American 
 investigators have recognized the difficulties in 
 obtaining exact statistics of the effect of recess 
 periods alone, uncontaminated by that of other 
 possible variables, such as workers, machines, and 
 materials. The value of resting periods in a war 
 operation is strikingly illustrated by a British 
 incident, in which two squads of soldiers, equal in 
 number, were ordered to dig equal lengths of a 
 certain trench. All the men of one squad worked 
 
28 THE HUMAN MACHINE 
 
 continuously and as hard as possible. The men 
 of the other squad were divided into groups, and 
 each group dug strenuously during five minutes 
 and then rested ten minutes. This organized 
 squad easily finished its job first. 
 
 The beneficial effect of resting periods on output 
 is thus not to be doubted, although further evi- 
 dence is desired regarding their optimum duration, 
 number and distribution throughout the working 
 period. They are probably of greater value in 
 strenuous work and work in which long spells pre-; 
 vail. The extensive experience of Vernon of the in- 
 vestigating staff of the British Health of Munition 
 Workers Committee in the study of labor in 
 munition factories has led him to conclude that 
 " A spell of five hours is probably too long for 
 almost any kind of labor." Our own experience 
 in American factories leads to the same conclu- 
 sion. But with a short working day, and 
 especially where production already approximates 
 capacity, the temporary gain resulting from a 
 brief rest may possibly be wiped out by the loss 
 involved in the time actually taken from work. 
 
VI 
 
 THE LENGTH OF THE WORKING DAY 
 
 This brings us naturally to the problem of the 
 length of the working day — perhaps the most 
 vital of all industrial problems in a consideration 
 of efficiency. Here the difference between the 
 non-living and the human machine stands out 
 clearly. Given the proper rate, the proper load 
 and the proper lubrication, with the non-living 
 machine one hour in the day is as good as 
 another; however long it works, there is no 
 diminution in the amount of its product. It is 
 not so with the human machine, with its curve 
 of output varying with the character of the work 
 and the capacity of the worker, and falling as 
 fatigue progresses. When long hours are imposed 
 upon the human machine the average amount of 
 work done per hour is diminished. This is largely 
 an unconscious process. It is obvious that there 
 is a limit to the working period and it is obvious 
 too that the problem of its proper length is really 
 a problem in human physiology. In attempting 
 to solve this problem nothing stands out more 
 
 29 
 
30 THE HUMAN MACHINE 
 
 clearly than the fact that a longer working day 
 does not necessarily mean a larger output. And 
 yet over and over again the mistake is made of 
 increasing the hours of labor when greater pro- 
 duction is desired, just as if the worker's body 
 were a thing of unyielding iron and brass, instead 
 of living and fatiguing tissues. This mistake was 
 made in England at the beginning of the war, 
 when the human machines of the factories were 
 driven until they broke. The attempt to impose 
 the same mistake upon our own war industries 
 is being made from time to time. It is not, per- 
 haps, of chief moment that a few lives are thus 
 destroyed, because destruction of life is a neces- 
 sary feature of war; but it is forgotten that the 
 war emergency is a matter not of days, but of 
 months and perhaps of years, and that the main- 
 tenance of the working power of the industrial 
 worker throughout months and years is as essen- 
 tial to victory as is the existence of the power 
 to-day. It is not, therefore, in the long run eco- 
 nomical to make the work of the day so strenuous 
 or so long continued as to diminish the work of 
 the following days and permanently decrease 
 output. 
 
 In deciding the proper length of the working 
 period the two factors of the fatiguing character 
 of the work and the capacity of the individual 
 
LENGTH OF WORKING DAY 31 
 
 workers should be taken into consideration (16). 
 One operation is more strenuous than another and 
 correspondingly taxes the powers of the worker 
 more. Moreover, one worker becomes fatigued 
 more readily than another. Consideration of a 
 period longer than twelve hours may be at once 
 dismissed, for there is sufficient evidence that 
 no one can profitably be employed in any task 
 habitually for a longer time than twelve hours. 
 So too there is little evidence at present that, for 
 most persons capable of undertaking industrial 
 occupation and for most occupations, eight hours 
 is too long for the work, although I am quite ready 
 to admit that this latter statement may be sub- 
 ject to revision in the future. Discussion may, 
 however, profitably be confined for the present to 
 these limits. 
 
 Now it has been frequently and indubitably 
 shown that a shortening of the period from the 
 upper toward the lower limit may increase not 
 only the output per hour, but also the total out- 
 put. It should here be borne in mind that, while 
 an increase in total production in a shorter time is 
 obviously advantageous to the employer, it is not 
 necessarily disadvantageous to the worker, be- 
 cause the longer resting period that follows gives 
 him a better opportunity for recuperation ; there is 
 no evidence that the added fatigue involved in the 
 
32 THE HUMAN MACHINE 
 
 greater expenditure of energy during the briefer 
 but more strenuous labor overbalances this gain. 
 Furthermore, even if the original output is merely 
 maintained or slightly decreased during the shorter 
 period, while the worker still gains physiologically, 
 the employer does not necessarily lose financially, 
 for the cost of production has been materially 
 decreased owing to the saving in the consumption 
 of mechanical power, lighting, heating, wear and 
 tear of machinery, and other sources of expense 
 that vary directly with the length of the working 
 period. 
 
 The older studies relating to length of working 
 period and output are well known. Prominent 
 among them, because of the care with which they 
 were followed and the fulness with which they 
 were reported, are the cases of the Salford Iron 
 Works at Manchester, England, the Engis Chem- 
 ical Works, near Liege, Belgium, and the Zeiss 
 Optical Works at Jena, Germany. At the Salford 
 Iron Works (17) the working week was shortened 
 in 1893 from fifty-three to forty-eight hours for its 
 1200 employees. The results were unmistakably 
 in favor of the decrease: Production was in- 
 creased; the proportion of time lost without leave 
 to the total time worked was decreased from 2.46 
 to 0.46 per cent; and, although, because of a fall 
 in the selling price of the goods, which happened 
 
LENGTH OF WORKING DAY 
 
 33 
 
 to occur during the year of observation, the cost 
 of wages increased 0.4 per cent, this was exactly 
 balanced by a saving in gas, electric lighting, 
 wear and tear, etc. The experiment was a marked 
 success, and assisted in the reduction to a forty- 
 eight hour weekly basis of the work in the British 
 government factories and workshops. At the 
 Engis Chemical Works (18) in 1892 the change was 
 made from a two-shift system of twelve-hour peri- 
 ods to a three-shift system of eight-hour periods, 
 the duration of actual work in the two cases being 
 ten and seven and one-half hours respectively, 
 with the result that in the shorter time the same 
 men at the same furnaces with the same tools and 
 raw material produced as much as before. At 
 the Zeiss Optical Works (19) in 1900 the working 
 day was shortened from nine to eight hours with 
 an average increase of about 3 per cent in the 
 daily output of the employees. 
 
 Similar evidence has been accumulating in more 
 
 Output of Employees in Shoe Manufacture 
 
 Period. 
 
 Working hours. 
 
 Production unit 
 
 per employee 
 
 per day, based 
 
 on pairs of shoes 
 
 shipped. 
 
 October-November 
 
 December- January 
 
 55 
 52 
 52 
 
 8.91 
 9.00 
 
 February-March 
 
 9.02 
 
 
 
34 
 
 THE HUMAN MACHINE 
 
 recent years. An American company (20) em- 
 ploying about 4000 hands, both men and women, 
 in the manufacture of shoes, reduced its weekly 
 working hours in December, 1916, from 55 to 52, 
 with the result shown in table on p. 33. 
 
 The very exact measurements by Vernon (21), 
 under the British Health of Munition Workers 
 Committee, afford most valuable evidence. Re- 
 duction of the actual weekly working hours of a 
 group of 56 men, engaged in the heavy labor of 
 sizing fuse bodies, from 58.2 tp 51.2, increased the 
 total output 22 per cent, as is shown in the accom- 
 panying table. 
 
 Output of Men Engaged in Heavy Work 
 
 
 Average Weekly 
 Houh8. 
 
 Relative 
 hourly- 
 output. 
 
 Relative 
 total 
 
 
 Nominal. 
 
 Actual. 
 
 output. 
 
 First period 
 
 66.7 
 62.8 
 56.5 
 
 58.2 
 50.5 
 51.2 
 
 100 
 122 
 139 
 
 100 
 
 Second period 
 
 Third period 
 
 106 
 122 
 
 With 80 to 100 women performing the moderately 
 heavy labor of turning aluminum fuse bodies in a 
 lathe, reduction of the actual working hours from 
 a weekly average of 66.2 to 54.8 resulted in a gain 
 of 11 per cent in total output; with a subsequent 
 reduction to 45.6 hours a gain of 9 per cent was 
 still maintained. The following table gives the 
 
LENGTH OF WORKING DAY 
 
 35 
 
 details. Note also the enormously increased hourly 
 output. 
 
 Output of Women Turning Aluminum Fuse Bodies 
 
 
 Average Weekly 
 Hours. 
 
 Relative 
 hourly 
 output. 
 
 Relative 
 total 
 
 
 Nominal. 
 
 Actual. 
 
 output. 
 
 First period 
 
 74.8 
 61.5 
 54.8 
 
 66.2 
 54.8 
 45.6 
 
 100 
 134 
 158 
 
 100 
 
 Second period 
 
 Third periud 
 
 111 
 
 109 
 
 
 
 A third instance, illustrated in the table below, is 
 also of interest. Here 40 women performing the 
 light labor of milling a screw thread on fuse bodies 
 were granted a reduction in working time amount- 
 ing to an actual weekly average of 26 per cent. 
 While their hourly output was increased by the 
 considerable figure of 33 per cent this was just 
 insufficient to maintain the former day's rate, 
 which fell by 1 per cent. 
 
 Output of Women Milling a Screw Thread 
 
 
 Average Weekly 
 Hours. 
 
 Relative 
 hourly 
 output. 
 
 Relative 
 total 
 
 
 Nominal. 
 
 Actual. 
 
 output. 
 
 First period 
 
 Second period 
 
 Third period 
 
 71.8 
 64.6 
 57.3 
 
 64.9 
 54.8 
 48.1 
 
 100 
 121 
 133 
 
 100 
 102 
 
 99 
 
 
 
36 THE HUMAN MACHINE 
 
 This result was due to the nature of the task, 
 which was chiefly a machine operation in which 
 the worker was forced to stand idly watching her 
 machine during four-fifths of the time and had less 
 opportunity than did the other workers for quick- 
 ening her speed. 
 
 These varied results make it clear that reduc- 
 tion in working hours, other conditions remaining 
 unchanged, affects production primarily in pro- 
 portion as the physiological factor enters into the 
 work. Here operations differ greatly. One is 
 treading on dangerous ground if he attempts to 
 predict an optimum working-day without an 
 analysis of the work itself. The fact is unmis- 
 takable, however, that the most reliable evidence 
 at present points toward an approximation of the 
 eight-hour working day as affording for a consid- 
 erable variety of occupations and for conscientious 
 workers the best condition for high productivity. 
 But the conclusion that an eight-hour day is 
 advisable universally in the industrial world must- 
 be regarded for the present as an assumption 
 hardly justified by the facts. The movement 
 toward a universal eight-hour day, now more than 
 sixty years old, has gained great headway and has 
 led to the correction of many abuses. It should 
 now be recognized that the question is one into 
 which physiology should step and that before a 
 
LENGTH OF WORKING DAY 37 
 
 decision on a strictly scientific basis can be reached 
 much further observation is needed. 
 
 Here I would utter a warning against the danger 
 of accepting mere opinion not based upon actual 
 facts. If the effect of a reduction of hours on 
 output is to be determined, it should be deter- 
 mined in the same manner in which the result of 
 any exact scientific inquiry is sought. Conjec- 
 tural estimates of output are of no value; quanti- 
 tative measurement alone is decisive. Not until 
 reliable statistics are obtained with the longer 
 working period should the reduction in time be 
 made. Then, in so far as possible, only the time 
 factor should be changed. In both the control 
 and the experimental series of observations, all 
 possible variables but the time factor should be 
 avoided, or should be allowed for if avoidance is 
 not possible. These variables may include the 
 number of employees actually working, the replace- 
 ment of skilled by unskilled workers, the time lost, 
 a change in the quality of the material, a change in 
 methods of working, and seasonal and other pos- 
 sibilities. Moreover, observations should extend 
 over a period of at least several months before a 
 conclusion is finally drawn. All effort indeed 
 toward determining the effects of a reduction in 
 the working hours in any factory or any industry 
 is wasted unless care is taken to conduct the inves- 
 
38 THE HUMAN MACHINE 
 
 tigation after the manner of an exact scientific 
 experiment.* 
 
 * The National Industrial Conference Board (54) is en- 
 gaged in a study of the effect on output of the reduction 
 of working hours in various industries, and has published 
 to date the results of its inquiries into the manufacture of 
 cotton and of shoes. Unfortunately the data were obtained 
 largely by the unreliable method of the questionnaire, rather 
 than by that of exact measurement. Inferences drawn from 
 such data can hardly be accepted as conclusive. 
 
VII 
 
 CAPACITY AND THE SELF-LIMITATION OF 
 OUTPUT 
 
 There is one feature of labor which I believe 
 to be one of the most potent and most universal 
 foes to efficiency. Natural working power varies 
 infinitely in individuals, and yet no one will, I 
 think, dispute the statement that few persons work 
 up to their individual capacities. Professor Wil- 
 liam James (22), clear-sighted observer and keen 
 thinker, once said that " As a rule men habitually 
 use only a small part of the powers which they 
 actually possess and which they might use under 
 appropriate conditions." This general human 
 tendency is found also among industrial workers. 
 It is even traditional with many and a thing to be 
 encouraged, especially with those who have worked 
 for years and have become accustomed to the tra- 
 ditional ways of labor. It is sometimes called, in 
 this country, " soldiering " and, in Great Britain, 
 " ca' canny." It may be a conscious, wilful pro- 
 cedure, or it may be partly or even wholly uncon- 
 scious. Many honest workers will tell you that it 
 is deliberate. It is sometimes ascribed to labor 
 
 39 
 
40 THE HUMAN MACHINE 
 
 unions as a deliberate policy, but it is found among 
 non-union workers as well. The American investi- 
 gators (1) have found that it occurs very commonly 
 in the form of what they have called " stereotyping 
 of output," that is, a form of output in which the 
 same individual or a group of individuals will turn 
 out day after day and week after week practically 
 the same quantity of finished product. In one 
 munition factory engaged in the manufacture of 
 fuses a large proportion of the force was thus work- 
 ing. In forming at a capstan lathe the large end 
 of the fuse one man finished exactly 1000 pieces 
 on each of 44 nights out of 45 that were observed; 
 in gauging the fuses 5 girls out of 6 that were 
 studied for one week, examined 1315 fuses each 
 day; in 99 cases of drilling certain holes, out of 163 
 observations extending over seventeen days, 1300 
 fuses were drilled by each battery of two operatives 
 in each spell, and 2600 in each day; and in an- 
 other drilling operation the output of each of 16 
 different workers, night after night, for one week 
 was 3600, no more and no less. If work were 
 stopped for a brief period for reasons beyond the 
 power of the worker to control, such as the tem- 
 porary crippling of a machine, the stoppage was 
 likely to be followed by a spurt and, without over- 
 working his powers, the worker finished the day 
 with the usual production to his credit. There is 
 obviously no general form of daily curve that is 
 
CAPACITY AND OUTPUT 41 
 
 afforded by such an output. It may or may not be 
 accompanied by fatigue. In the factory men- 
 tioned, and this seems to be general with repetitive 
 work, piece-rates were paid, and the worker by 
 doing more could earn more wages, and yet he lim- 
 ited his work. 
 
 The cause of this self-limiting of production is 
 probably quite varied. It is often to be traced to 
 plain laziness. One often finds too a loyal dis- 
 inclination among capable workers to surpass their 
 fellows, and often a more or less unconscious recog- 
 nition that a certain amount is enough for a day's 
 work. Sometimes the fault lies with the foreman, 
 who encourages the performance of a certain 
 amount as the traditional and proper output of 
 his department, or as that which conforms best 
 with the routine of the factory. But over and 
 above all other causes the self-limitation of pro- 
 duction is to be laid most commonly to a custom 
 that has long prevailed and still prevails in indus- 
 trial management, that of lowering an established 
 piece-rate when in the opinion of the management 
 the worker is earning too large wages. Sometimes 
 this is done directly, sometimes it is done indirectly 
 by slightly altering the operation and calling it 
 new, although it may accomplish the same end. 
 This cutting of piece-rates has been so prevalent 
 in the past — it is the boast of one employer that he 
 had cut the rate on a particular operation five times 
 
42 THE HUMAN MACHINE 
 
 in succession — that the experienced worker has 
 learned to expect it when, by his own exertions, 
 his wages run high, and thus his original confidence 
 in his employer has been undermined and his orig- 
 inal ambition to work hard, however honest, has 
 been thwarted. The choosing of a proper piece- 
 rate for an operation, one that will justly compen- 
 sate the worker for his services and allow a fair 
 profit to the employer, is admittedly a difficult 
 mattar; but with an experienced rate-setter or by 
 the aid of tims studies mistakes that involve serious 
 financial loss should rarely occur. On the other 
 hand, the loss of the worker's confidence in the 
 honesty of his employer is of profoundly serious 
 moment, inimica to his best efforts and sure to 
 involve the employer in a decrease of pecuniary 
 profit. Nothing can be more detrimental to the 
 industrial success of both than a feeling of mutual 
 distrust. Their re'ations ought to be those not of 
 opponents in a game, each trying to outdo the 
 other, but rather of companions in an enterprise 
 to be achieved through the best efforts of both. 
 The employer should pay a wage that is directly 
 proport onal to the effort that the worker ex- 
 pends, and this once promised should be continued. 
 If th's is done the worker is under equal obliga- 
 tion not to limit his production, but to work up to 
 the capacity that is in him. This is especially a 
 duty where he is granted a short working day. 
 
\ III 
 
 THE MAINTENANCE OF WORKING POWER. 
 OVERTIME 
 
 I have spoken so far only of the labor of the 
 single work-day and the fatigue that results from 
 it. That there exists also a weekly course of 
 fatigue is generally assumed. There have been 
 few exact studies of this subject, but there is a 
 certain amount of reliable evidence that weekly 
 fatigue regularly exists. Thus Martin, Withington 
 and Putnam (23) have found in students a pro- 
 gressive diminution in the sensibility of the skin 
 from Monday to Saturday, and they ascribe this 
 to the progressive fatigue of the week. The indus- 
 trial output curve for the week, however, rarely 
 shows the effect of a weekly fatigue. It is per- 
 sistently low on Monday, higher on Tuesday, and, 
 while usually at a fairly high level with fluctua- 
 tions during the week, does not necessarily fall on 
 Saturday. The low output on Monday, the so- 
 called " Monday effect," is well recognized and is 
 usually ascribed to Sunday dissipation, especially 
 drinking. A more reasonable explanation is that 
 suggested by Kent (24) that the low output is due 
 
 43 
 
44 THE HUMAN MACHINE 
 
 to a lack of neuromuscular coordination following 
 a day of rest ; as the result of the abstention from 
 work at the week-end operations are to some extent 
 forgotten; by the training imposed by the work 
 of Monday, however, they are quickly learned 
 again and the physiological mechanism comes back 
 to its usual state of efficiency. The rise in output 
 from Monday to Tuesday is thus a " practice 
 effect." It may seem strange that the output 
 curve does not fall toward the end of the week; 
 but the absence of a fall cannot be interpreted as 
 necessarily an indication that no fatigue is present. 
 It may merely show that with the conditions under 
 which the work studied has been performed there 
 is not sufficient cumulative fatigue to make itself 
 evident in this particular form of physiological 
 activity. There is always too the unavoidable 
 suspicion that the operatives are not working up 
 to their capacities. There is, moreover, to be 
 considered the fact that the human machine is 
 peculiar in that it is always played upon and its 
 efficiency is partly determined by mental influ- 
 ences, and it is not impossible that the approach 
 of the week end with its expected release from 
 labor may buoy up the workers and mask any tis- 
 sue fatigue that might otherwise manifest itself. 
 That psychical influences do mask fatigue is well 
 illustrated by the case of the six-day bicycle riders 
 
MAINTENANCE OF WORKING POWER 45 
 
 in New York, observed by Ayres (25), who rode 
 at an average of 18.8 miles an hour when there 
 was no music, but speeded up to 21 miles when 
 the band played. 
 
 In order to preserve the working power daily 
 fatigue should not be so great that it cannot be 
 substantially removed by the night's rest; weekly 
 fatigue ought likewise to be dispelled by the rest 
 of Sunday. If this is not accomplished, if there is 
 a residue of this powerful obstacle to efficiency 
 accumulating from day to day and from week to 
 w r eek, serious results will surely follow. This was 
 precisely the situation in the munitions industry 
 of England. Sixteen months after the war began 
 the British Health of Munition Workers Commit- 
 tee (2) wrote: " Taking the country as a whole the 
 Committee are bound to record their impression 
 that the munition workers in general have been 
 allowed to reach a state of reduced efficiency and 
 lowered health which might have been avoided 
 without reduction of output by attention to the 
 details of daily and weekly rests." And again, 
 twenty-two months later, the Committee wrote: 
 " The conditions are not the same now as they 
 were in the early days of the war; not only have 
 large numbers of the youngest and strongest 
 workers been withdrawn for military service, but 
 those who remain are suffering from the strain in- 
 
46 THE HUMAN MACHINE 
 
 separable from a continuous period of long hours 
 of employment. . . . The effects of the strain may- 
 even have been already more serious than appears 
 on the surface, for while it is possible to judge 
 roughly the general condition of those working in 
 the factory to-day, little information is available 
 concerning the large number of workers who, for 
 one reason or another, and often because they find 
 the work too arduous, are continually giving up 
 their job." This experience of England ought 
 to serve as a lesson to other countries, and especi- 
 ally to America. 
 
 A particularly insidious way of nullifying the 
 advantages of a short working-day that is not un- 
 common is the imposition of overtime, keeping the 
 employee for an evening of work after the day's 
 work is done. Here a peculiarity of the human 
 machine is of interest. Mosso (26) showed long 
 ago that fatigue does not increase in arithmetical 
 proportion to the increase in work done, but that 
 added work imposed upon an already fatigued 
 individual is disproportionately more fatiguing and 
 requires a longer time for recuperation. Kent (8) 
 found that the keenness of the sight of industrial 
 workers is diminished in a greater degree by a day 
 with overtime, than by a day of the usual length. 
 When overtime is imposed the further call upon 
 the depressed tissues can, indeed, be answered for a 
 
MAINTENANCE OF WORKING POWER 47 
 
 while by further action — the human machine can 
 spurt — but the more healthful occupation of the 
 evening, in view of the work of the morrow, would 
 be one of recreation and rest. If overtime is ever 
 thought necessary, as in a real and serious emer- 
 gency, it should be only occasional and should be 
 followed by an added compensating resting period. 
 
 What is said of overtime applies with equal 
 force to Sunday labor following six days' occupa- 
 tion. Here, again, the example of England is 
 instructive. As a direct result of the study of 
 industrial fatigue since the war began the British 
 Committee puts it tersely in saj'ing " It is almost 
 a commonplace that seven days' labor only pro- 
 duces six days' output," and adds that in Great 
 Britain " Sunday labor for men is now greatly 
 restricted in amount and has been practically 
 abolished for women and young persons." 
 
 A further matter of importance may here be 
 mentioned. ^Vn observant visitor to the factories 
 cannot fail to notice that he rarely sees old men or 
 women among the employees. This is so evident 
 that the presence of an aged worker appears 
 anomalous. There is a widespread opinion that 
 forty-five represents the retiring age for most in- 
 dustrial workers. In an investigation of 1761 brass 
 foundrymen in Chicago in 1911, Hayhurst (27) 
 found that there were but 17, or 0.97 per cent, over 
 
48 THE HUMAN MACHINE 
 
 fifty years of age, and but 180, or 10.2 per cent, 
 estimated at over forty years. The question im- 
 mediately arises: What is responsible for the 
 absence of workers beyond middle life; and the 
 answer inevitably comes to mind that the rigor 
 of the game incapacitates them at an age. when 
 human beings are expected still to be doing ex- 
 cellent work. If this is so, the accumulated 
 fatigue of many years is the decisive factor. The 
 remedy would appear to be a diminution in the 
 hours of labor and the installation of other con- 
 ditions not so severe for the human machine and 
 conducive to its longer usefulness. In a field in 
 which accurate data are largely wanting and an 
 intensive study is much needed, it is impossible 
 to draw decisive conclusions, but the subject offers 
 foo"d for enticing speculation. It may yet prove 
 to be a vital one in the war industries, for the man- 
 ufacture of war supplies may possibly yet devolve 
 largely upon men and women beyond the age of 
 forty-five. 
 
IX 
 
 THE LABOR TURNOVER 
 
 There is still another constant feature of occu- 
 pational work which is a bar to the highest degree 
 of efficiency, namely, the change in the personnel 
 of the workers. This is called the " labor turn- 
 over." Its extent is remarkable, practically no 
 factory is free from it, and it surpasses in amount 
 all estimates of those who have not examined 
 actual statistical data concerning it. It is con- 
 sidered such a serious matter that it has recently 
 been receiving considerable attention from em- 
 ployers and industrial administrators. In a recent 
 study of twelve factories in the metal industry, 
 Alexander (28) found that 72.8 per cent of all em- 
 ployees engaged during 1912 were entirely new to 
 the factories in which they worked and that in 
 order to increase the working force by 6G97 during 
 the year 42,571 persons were engaged. The change 
 is less among the more skilled than the less skilled 
 workers. But, whether skilled or unskilled, when 
 it is considered that such figures represent ma- 
 chines, human machines, installed and replaced, 
 
 49 
 
50 THE HUMAN MACHINE 
 
 the wastefulness of the process appears evident. 
 No figures are available to show how the war has 
 affected labor turnover, but it seems fair to as- 
 sume that it has increased as the result of "war 
 conditions. 
 
 The mere pecuniary cost of a great change in 
 the laboring force is a large item, being estimated 
 by Alexander as $53.92 for each new employee. 
 This total includes the cost of such features in- 
 volved in the employment of new workers as the 
 clerical work of hiring, instruction of new em- 
 ployees, increased wear and tear of machinery and 
 tools, reduced production, increased amount of 
 spoiled work, and more accidents. Almost no 
 exact data exist relative to these factors, but the 
 Public Health Service has been able to discover 
 in several departments of a large munition fac- 
 tory a significant parallelism between the number 
 of accidents and the inexperience of the working 
 force. One of the curves is reproduced in Fig. 
 8, page 75. It must be believed that the low 
 output of a new worker contributes the most con- 
 siderable item to the cost of the labor turnover, 
 and during the present emergency this is a very 
 •serious matter. It is, therefore, desirable to seek 
 out the causes of the labor turnover and to apply 
 the remedies, if such there be. 
 
 The Public Health Service (1) has obtained the 
 following statistics regarding the reasons for 
 
THE LABOR TURNOVER 51 
 
 employees leaving one of the munition factories 
 during a period of six months: 
 
 A — Reason known to firm 992 
 
 Dismissed (disciplinary ) 590 
 
 Unsatisfactory 229 
 
 Disobedience to orders 86 
 
 Moral delinquency 66 
 
 Loafing, Btaying out 65 
 
 Dangerous 58 
 
 Refusal to work 27 
 
 Insolence to foreman 26 
 
 Sleeping at work 18 
 
 Disobedience to factory rules, e.g., 
 smoking 15 
 
 Private circumstances outside factory 222 
 
 Removal from city 109 
 
 Military call 78 
 
 Family difficulties 22 
 
 Illness 10 
 
 Jail 2 
 
 School 1 
 
 Resigned 112 
 
 General — " gave notice " 87 
 
 No place to stay 25 
 
 Paid off (discharged honorably) .... 68 
 B — Reason unknown to firm. Emploj'ees 
 absent more than two weeks with- 
 out notice 9,442 
 
 Here it appears that more than 90 per cent of 
 the retiring force left their employment for reasons 
 unknown to the company. This experience is 
 probably not exceptional. The analysis does not 
 go farther, but many probable reasons at once come 
 to mind. There will always be a certain number 
 
52 THE HUMAN MACHINE 
 
 of long illnesses, deaths, and specific personal rea- 
 sons not connected with the factory or its manage- 
 ment, and there will always be a floating labor 
 element, drifting hither and thither, and never 
 content to remain long in one place. But it is 
 probable that the majority of industrial workers, 
 like other human beings, prefer to find their niche 
 in the world and remain in it. If, therefore, they 
 do not remain long in the place which they have 
 entered it is because there is a lack of adaptation 
 between them as human beings and their environ- 
 ment. This may relate to wages, length of working 
 day, nature of the work and their fitness for it, 
 danger of accidents, physical conditions of the 
 factory affecting comfort and welfare, their fore- 
 man or their fellow workmen, or other features 
 with reference to which they do not, or think that 
 they do not, fit. Specific remedies are, therefore, 
 indicated in specific cases, and a careful search for 
 the causes and the application of the proper reme- 
 dies should constantly be made by the employing 
 company. But, in general, I believe that whatever 
 promotes individual efficiency, whatever enables 
 the individual machine to work in accordance with 
 physiological laws, whatever leads to more com- 
 plete adaptation of the worker to his task, will 
 lessen his desire to leave it and will lighten the 
 burden of the labor turnover. 
 
X 
 
 THE INDUSTRIAL EFFICIENCY OF WOMEN COM- 
 PARED WITH MEN 
 
 The war has increased enormously the total 
 number of industrial workers, both men and 
 women. Factories that formerly employed hun- 
 dreds now make use of thousands, and new 
 factories springing up here and there make new cen- 
 ters of occupation. A fact that is of special inter- 
 est is the relatively greater increase in the number 
 of women than of men workers. It is stated (29) 
 of Great Britain that women have been substituted 
 for men in practically all trades and that according 
 to official figures in July, 1917, 1,392,000 women 
 were taking men's places. Women, as never be- 
 fore, are becoming a prominent feature of indus- 
 trial life, both in this country and the countries of 
 the other Entente Allies. An inquiry is, there- 
 fore, pertinent into the efficiency of the woman as 
 compared with the man worker. 
 
 Here I wish to utter a word of preface. Think- 
 ing persons have long since passed the stage where 
 the question of man's superiority in general and 
 woman's inferiority is discussed — there is no such 
 
 53 
 
54 THE HUMAN MACHINE 
 
 question. It is equally clear that there exist be- 
 tween the sexes marked biological differences, an- 
 atomical, physiological, psychological. I shall not 
 discuss the question, which has a real existence, in 
 how far these differences are genetic, inherent in 
 the nature of the individual and transmissible by 
 inheritance, and in how far they are the result of 
 education, training, social environment and op- 
 portunity. But it must be granted that the dif- 
 ferences in anatomical features, and they are 
 many and profound, are inherited; and if this be 
 so, it is, I think, idle to claim that the main physi- 
 ological and psychological differences, also many 
 and profound, are chiefly the result of differences 
 in training and social environment. Nevertheless, 
 whatever their origin, the differences do exist and 
 they must be reckoned with in the determination 
 of the relative fitness of the two sexes for indus- 
 trial work and their relative industrial efficiencies. 
 The lesser muscular strength of women is obvi- 
 ous. Miss Thompson (30), in summarizing the re- 
 sults of her own and others' tests on various phases 
 of motor ability, the keenness of the senses and 
 certain intellectual qualities, finds that men have 
 a shorter reaction time than women, with a smaller 
 mean variation in the time, a greater rapidity of 
 movement, a slower oncoming of fatigue, and a 
 greater accuracy of movement; while women excel 
 
WOMEN COMPARED WITH MEN 55 
 
 men in the rapidity of forming new motor coordi- 
 nations. Men too have a keener vision in the per- 
 ception of light and finer discrimination in lifted 
 weights, tastos, and the determination of the areas 
 of visible objects; while women are keener in 
 detecting stimuli in skin sensibility, such as touch 
 and pain effected through pressure, in taste, smell, 
 and color, and have finer chscrimination in the 
 pitch of sounds and in color. On the whole men 
 excel in motor ability, and women in delicacy of 
 the senses. As to the intellectual faculties men 
 are superior in ingenuity, and women in memory 
 and the rapidity of forming mental associations. 
 The total amount of general information possessed 
 by the two — I am still following Miss Thompson's 
 summary — is essentially the same where they have 
 taken the same course of education, although men 
 are somewhat better informed in scientific and 
 women in literary subjects. My own experience 
 with men and women in the laboratory has shown 
 me — and I think this is almost a universal experi- 
 ence — that women have less initiative and re- 
 sourcefulness in planning a research or an experi- 
 mental method, but that once it has been planned 
 they will perform the required experiments with a 
 high degree of accuracy and commendable per- 
 sistence. If, however, in the course of the work 
 the apparatus that they are using goes wrong 
 
56 THE HUMAN MACHINE 
 
 mechanically, they are not so successful as are most 
 men in discovering the cause of the trouble and 
 eliminating it. 
 
 These differences between men and women make 
 it clear that the first pertinent question here is 
 not that of the greater or less general industrial 
 efficiency of the woman as compared with the man 
 worker, but rather the question of what kinds of 
 industrial operations are best adapted to each. 
 Women are obviously debarred from the mus- 
 cular ly more severe tasks. In those requiring con- 
 stant change and a constant call upon a consider- 
 able degree of mechanical ingenuity women may 
 not be expected to be so generally successful as 
 men. But with the lighter operations, where the 
 same act is constantly repeated, which make up 
 now a great proportion of industrial tasks, women 
 find a suitable field for their activities. An ob- 
 server finds a considerable number of women in 
 our munition factories doing lathe work and doing 
 it with apparently the same degree of efficiency as 
 men. The making of both guns and ammuni- 
 tion requires constant inspection of the manufac- 
 tured parts to insure their accuracy and the elimi- 
 nation of imperfect pieces, and here women have 
 shown themselves particularly capable. Such in- 
 spection, which involves not only very careful ob- 
 servation but often very accurate measurement 
 
WOMEN COMPARED WITH MEN 57 
 
 and in which rapidity of decision and action is re- 
 quired, is now indeed performed chiefly by women. 
 Wherever men and women are working at the same 
 task and one apparently suited to both I do not 
 find that accurate data have yet been secured to 
 warrant an inference as to their relative degrees 
 of efficiency. The general opinion, as I have been 
 able to gather it from a few of the managers of 
 our munition factories, seems to be that in such 
 tasks woman's efficiency equals man's. 
 
 The question of relative health must be taken 
 into consideration. Statistics from various coun- 
 tries show that working women are more subject 
 to illness than are working men, their morbidity 
 is greater. The statistics of the Local Sickness 
 Fund of Leipsic (31) for one hundred wage-earning 
 persons observed are as follows: 
 
 Age group. 
 
 Cases of sickness per 100 
 
 PERSONS. 
 
 Men. 
 
 Women. 
 
 Under 15 years 
 
 3S.0 
 37.6 
 36.3 
 3S.0 
 44.3 
 51.7 
 60.2 
 75.7 
 
 29.0 
 
 15-20 
 
 36.4 
 
 20-25 
 
 42.1 
 
 25-35 
 
 50.2 
 
 35-45 
 
 55.3 
 
 45-55 
 
 54.3 
 
 55-65 
 
 54.9 
 
 65-75 
 
 66.6 
 
 
 
58 THE HUMAN MACHINE 
 
 This excess of illness occurs especially between 
 the ages of twenty and fifty-five, although it seems 
 not to be due to child-bearing alone. Working- 
 females younger and older than these age limits 
 show in general less morbidity than do working 
 males. With minor illnesses women continue at 
 their work more steadily than do men. Not- 
 withstanding this fact, the absences of women 
 from their work because of illness are much more 
 frequent than are the absences of men. Thus the 
 Mutual Aid Society of Silk Workers at Lyons (32) 
 reports that between the ages of twenty and forty 
 the days lost by its women members, because of 
 sickness, were more than twice those lost by men. 
 Statistics obtained by the U. S. Public Health 
 Service (33) show that among 16,000 government 
 employees in the Federal departments at Wash- 
 ington in 1914, men lost on account of sickness an 
 average of 4.82 days and women an average of 8.90 
 days, also more than twice as many. There is a 
 general tradition that the menstrual function 
 causes a periodic diminution of general efficiency 
 in woman's body, but this is hardly supported by 
 the more exact inquiries. One of the latest and 
 apparently most reliable of these, a research per- 
 formed by Mrs. Hollingworth (34) at Columbia 
 University, in which various familiar tests of the 
 psychological laboratory were used, leads to the 
 
WOMEN COMPARED WITH MEN 59 
 
 conclusions that: " Careful and exact measure- 
 ment does not reveal a periodic mental or motor 
 inefficiency in normal women. . . . The varia- 
 bility of performance is not affected by physiolog- 
 ical periodicity. No regularly recurring period of 
 maximum efficiency within each month is discern- 
 ible." Notwithstanding this conclusion, appar- 
 ently justified from the results that were ob- 
 tained by the methods used, one of my graduate 
 students, Miss Epstean, in an investigation of 
 the total strength of ten healthy young women, 
 conducted by means of almost daily tests with the 
 spring balance method extending over five months, 
 reveals an average loss of muscular strength of 
 about 5 per cent during the menstrual days. 
 
 Women are more susceptible than are men to 
 industrial poisons. There is general agreement 
 that they are more susceptible to the evil physical 
 conditions of industrial life, such as long working 
 hours, hasty meals, constant standing, lack of 
 resting intervals, and so on. 
 
 All the considerations here cited combine to 
 demonstrate that the female body considered as a 
 machine is different in certain respects from the 
 male body and that the conditions under which the 
 greatest degrees of efficiency can be secured for the 
 two, respectively, are probably different in cer- 
 tain features. Because of this and because of the 
 
60 THE HUMAN MACHINE 
 
 fact that women have become an indispensable fac- 
 tor in the industrial world there is needed a care- 
 fully controlled experimental study of the problem 
 of women's labor from the physiological stand- 
 point. 
 
XI 
 
 NIGHT WORK IN COMPARISON WITH DAY WORK 
 
 Long ago night work had become an established 
 industrial custom, especially for men. Night 
 work is excusable where the nature of the processes 
 is such that continuous operation is required, where 
 interrupting the series of events essential to the 
 manufacture would inevitably ruin the material 
 already well along in the process of production. 
 Even where a continuous process is not essential 
 night work is understandable, for it can be argued 
 on apparently reasonable grounds that it is uneco- 
 nomical to allow productive equipment to remain 
 idle for one-half or two-thirds of every twenty-four 
 hours. But at the outset of every discussion of 
 the topic it should be borne in mind that from the 
 standpoint of the human machine night work is 
 always abnormal. Man is a diurnal, not a noc- 
 turnal, animal, and any attempts to change his 
 innate habits in this respect are bound to inter- 
 fere with his physiological processes. Man's body 
 needs the stimulus of sunlight and is adapted to 
 the atmospheric conditions of the day. Some of 
 
 61 
 
62 
 
 THE HUMAN MACHINE 
 
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 o .c 
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 37.0 
 36.5 
 36.0 
 
 F. 
 
 98.6° 
 
 97.9° 
 96.8° 
 
 6 
 
 his physiological proc- 
 esses exhibit a regular 
 curve of variation 
 through the twenty- 
 four hours, one of the 
 best known being that 
 of bodily temperature, 
 with its gradual rise 
 during the day to a 
 maximum late in the 
 afternoon, and a grad- 
 ual fall during the 
 night to a minimum 
 in the early morn- 
 ing (Fig. 5). Under 
 very exceptional cir- 
 cumstances of living 
 this cycle may be re- 
 versed by turning the 
 day into night, and 
 vice versa. Thus 
 Simpson and Gal- 
 braith (35) obtained 
 such a reversal in mon- 
 keys by keeping them 
 awake and active dur- 
 ing the night and al- 
 lowing them to sleep 
 
NIGHT WORK AND DAY WORK 63 
 
 in sound-proof and light-proof cages during the 
 day, and Linhard (36) in the long night of an 
 Arctic winter, dark and silent, found that the 
 rhythm of bodily temperature could be reversed 
 at will by changing the alternation of rest and 
 activity. But Benedict's (37) observations are 
 more pertinent to our present subject. By means 
 of an apparatus that recorded the bodily tempera- 
 ture continually throughout the twenty-four 
 hours he observed two subjects, one a customary 
 day-worker who had changed to night-work nine 
 and eleven days, respectively, before the two 
 series of observations were made; and the other 
 a night-watchman who had had five years of un- 
 interrupted night service. In both cases the 
 curves of temperature showed deviations from the 
 curves of an individual living the more normal 
 life, but — and here is the important point — in 
 neither case was there an inversion of the usual 
 day and night curve, in both there was the usual 
 fall through the evening to a minimum in the early 
 morning. It is widely believed that bodily vigor 
 is low in the early morning and that the greatest 
 number of deaths occur then; there is some statis- 
 tical evidence for this. 
 
 The war emergency has increased enormously 
 the amount of night work of both men and women. 
 This is especially so in England. It, therefore, 
 
64 THE HUMAN MACHINE 
 
 becomes desirable to inquire into the efficiency of 
 night in comparison with day work. 
 
 A common custom in factories possessing a ten- 
 hour working day with no Sunday work is to make 
 the duration of the night work twelve hours for 
 the five working nights of the week, thus equalizing 
 the weekly lengths of the two shifts. The Public 
 Health Service (1) has investigated the output of 
 men engaged in certain operations in one of our 
 munition factories under such conditions and has 
 obtained certain curves of production, one of 
 which is here reproduced (Fig. 6). The operation 
 consisted of drilling and reaming a hole in the 
 bottom closing screw of a fuse, and the task re- 
 quired the use of several tools and accurate muscu- 
 lar coordination. Work began at 6:20 f.m. and 
 continued uninterruptedly until midnight. Lunch- 
 eon was then eaten, but was allowed to occupy 
 only twenty minutes. The second spell continued 
 from 12 :20 until 6 :40 A.M. The output of the first 
 spell showed a rise followed by a fall — practice 
 effect and fatigue. The brief luncheon recess was 
 insufficient for recuperation in the work illus- 
 trated, although in some other operations ob- 
 served there was a slight recovery of working 
 power. In the second spell output again rose and 
 then fell during five hours, up to which point the 
 night's curve had not differed essentially from that 
 
NTOHT WORK AND DAY WORK 65 
 
 620 7 
 
 Fkj. 6. — Curve of output in night work. The height of each 
 point in the curve above the base line represents the output 
 of the corresponding hour. Men workers; lathe operation; 
 shift of twelve hours and twenty minutes. (By courtesy 
 of the U. S. Public Health Service.) 
 
66 THE HUMAN MACHINE 
 
 of the day for work of a similar character. But 
 then appeared a striking feature, for from about 
 5 o'clock on, production dropped suddenly and 
 during the final forty minutes almost nothing, in 
 some other operations literally nothing, was pro- 
 duced. The actual figures are here reproduced. 
 
 Output of Night Wokk 
 
 Hour. 
 
 Output. 
 
 Drilling and reaming; 
 
 total of 56 observations. 
 
 6.20-7 p.m. 
 
 10,349 
 
 7-8 
 
 10,730 
 
 8-9 
 
 11,220 
 
 9-10 
 
 11,011 
 
 10-11 
 
 10,925 
 
 11-12 
 
 10,591 
 
 12.20-1 a.m. 
 
 10,368 
 
 1-2 
 
 10,728 
 
 2-3 
 
 10,677 
 
 3-4 
 
 10,743 
 
 4-5 
 
 10,311 
 
 6-6 
 
 7,932 
 
 6-6.40 
 
 152 
 
 The investigators noted the average time re- 
 quired for performing certain operations during 
 the successive four periods of three hours each 
 throughout the night and found that this grad- 
 ually lengthened as the night passed on, the suc- 
 cessive figures in seconds being 12, 13.3, 16.5 and 
 17.4.- Furthermore, a count of the number of 
 
NIGHT WORK AND DAY WORK C7 
 
 men found sleeping at every quarter of an hour 
 dining the last three hours of the shift gave the 
 following figures, the total number of men work- 
 ing in the department at the time being 74. 
 
 Hour a.m. 
 
 Number of men 
 sleeping. 
 
 UOL'R A.M. 
 
 Number of men 
 sleeping. 
 
 3.30 
 
 5 
 
 5.15 
 
 2 
 
 3.45 
 
 3 
 
 5.30 
 
 2 
 
 4.00 
 
 4 
 
 5.45 
 
 4 
 
 4.15 
 
 
 
 6.00 
 
 2 
 
 4.30 
 
 4 
 
 6.15 
 
 14 
 
 4.45 
 
 1 
 
 6.30 
 
 2 
 
 5.00 
 
 5 
 
 
 
 These results suggest the remedy for the great 
 deterioration in production in the latter part of 
 the night shift: End the work at 5 a.m or even 
 before that and send the workers home and to bed. 
 If this were done and the night work were short- 
 ened to ten hours it is quite probable that the 
 night's production would be actually increased. 
 
 That, in general, night labor is not so efficient 
 as day labor is clearly shown by certain observa- 
 tions made by the British Committee on the out- 
 puts of the two shifts. Thus Greenwood (38) 
 found that where the actual working time was 
 nearly the same in the day and the night shifts of 
 a cartridge factory the women night workers pro- 
 
68 THE HUMAN MACHINE 
 
 duced in the case department in two periods that 
 were observed 17 and 12 per cent less, respec- 
 tively, than the women day workers, and in the 
 bullet department in one period 10 per cent less. 
 Moreover, the regularity of employment was de- 
 cidedly inferior with the night workers, they hav- 
 ing lost 8.70 per cent of time, as compared with 
 only 5.63 per cent lost by the day workers. In 
 certain operations in the making of 3-inch shrap- 
 nel shells by men Vernon (38) found the night 
 workers to produce on the average about 6 per 
 cent less than the day workers. There is a gen- 
 eral consensus of opinion that the product of night 
 work is inferior in quality to that of day work and 
 that it contains a larger proportion of spoiled 
 goods. 
 
 Statistics show that more accidents occur during 
 the night hours than during the day hours. This 
 is well demonstrated by the observations made by 
 Chaney (39) under the U. S. Department of Labor 
 in a large steel plant during a period of six years, 
 the excess of the night rate over the day rate 
 amounting to 11.6 per cent (Fig. 7). 
 
 There is a general consensus of opinion that 
 night work is more deleterious to health than is 
 day work, and this opinion is supported by incon- 
 testable evidence; but in the present state of our 
 knowledge it is hardly possible, nor indeed for our 
 
NIGHT WORK AND DAY WORK 69 
 
 1905 
 1906 
 1907 
 
 UOB M 
 
 1909 
 
 1910 
 
 Blast 
 Furnaces 
 
 Bessemer 
 
 Open 
 
 Hearth 
 
 Polling 
 
 Mills 
 
 Mechanical 
 Yards 
 
 2ty 
 
 103 
 
 , '<i$% 
 
 ( Durlna 1908 many 
 
 . danrjerous operations 
 
 1 74 | entirely suspended 
 at night.) 
 
 ™ 
 
 127 
 
 153 
 
 NIGHT ET 
 
 DAYQ 
 
 Fig. 7. — Day and night accident rates per lOOO workers in a 
 lnrRp steel plant, by years and departments. (By courtesy 
 of the U. S. Department of Labor.) 
 
70 THE HUMAN MACHINE 
 
 present purpose, is it necessary, to differentiate 
 between deleterious effects per se, resulting from 
 such conditions as the attempted imposition of an 
 unphysiological rhythm and the lack of beneficial 
 sunshine, and deleterious effects resulting from the 
 fact that under our social conditions the day's 
 recuperation of the night worker is rarely equal to 
 the night's recuperation of the day worker. Night 
 work entails a diminution of sleep. The day's 
 light, the day's sounds, the irresistible lure of an 
 active world, and, with a married woman, domestic 
 duties, in a home where children must be cared 
 for, meals must be prepared, and clothing must be 
 washed — all these prevent sleep. The New York 
 State Factory Investigating Commission (40) 
 found in one large plant that the married women 
 who worked at night obtained about four and one- 
 half hours of sleep in the day time. Here in itself 
 is a powerful bar to efficiency. The bad effects of 
 night work on health have been especially ob- 
 served in women workers, with their greater sus- 
 ceptibility to illness (41). What is a physical tax 
 on man is a physical surtax on woman, and it 
 cannot be allowed that this form of burden is 
 justifiable even in the emergency of war. 
 
 I have shown that night work is characterized 
 by certain distinctive features: It imposes on a 
 physiological organism attuned to one sequence of 
 
NIOIIT WORK AND DAY WORK 71 
 
 events a different and abnormal sequence; it is 
 
 characterized by greater fatigue Hum is day work; 
 it is interrupted by sleep; its curve of output tail- 
 off at an excessive rate in the morning hours; its 
 total output is less than with day work; its acci- 
 dent rate and its proportion of lost time are in 
 excess over those of the day; it has a deleterious 
 effect on health. All these features are inimical 
 to a high degree of efficiency. 
 
 The case against it appears to be black. How 
 can its evils be lessened? The British Committee 
 (38) has suggested one plan, and that is by making 
 it not continuous, week after week, but alternating 
 periods of night work with periods of day work. 
 They have, indeed, observed this plan in women's 
 factories with hundreds of operatives whose work 
 was changed from night to day and vice versa, 
 in some cases every week, in other cases every 
 month. In nearly every group of workers follow- 
 ing this plan that were observed, both men and 
 women, there was practical equality of the night 
 and the day outputs, and the total output of the 
 day periods did not seem to be lessened because of 
 the existence of the previous night periods. With 
 women, however, the equality of output appeared 
 to be confined to the more monotonous operations; 
 with those less monotonous there was evidence 
 that the night's inferiority was still maintained. 
 
72 THE HUMAN MACHINE 
 
 The Committee expresses no opinion as to the best 
 length of the alternating periods. Frequent 
 changes have the disadvantage of giving too little 
 time for adjustment of one's habits, especially that 
 of sleeping. If night work must be performed, 
 however, the discontinuous system appears to in- 
 volve less inefficiency than the continuous system. 
 The American observers have not given special 
 study to the relative merits of the two systems, 
 but their observations point to the general con- 
 clusion that a long night shift, such as twelve 
 hours, is unprofitable. The final two hours at 
 least, with their broken time and little output, 
 might well be cut off and the worker be sent home 
 to gain a better recuperative preparation for the 
 labor of the following night. It ought, however, 
 clearly to be understood that these devices of dis- 
 continuity and brevity are but a subterfuge; they 
 offer only a mitigation of an evil. Night work is 
 unnatural, unphysiological, abnormal, and it must 
 ever remain so. It should not be allowed for 
 women, and resort to it for men can only be justi- 
 fied by exceptional circumstances. 
 
XII 
 
 INDUSTRIAL ACCIDENTS 
 
 In any comprehensive discussion of industrial 
 efficiency accidents to the workers must be con- 
 sidered. It has been estimated that in the United 
 States 30,000 wage-earners are killed annually and 
 at least 500,000 more are seriously injured. By 
 far the greater number of industrial accidents must 
 be laid in part at least to the account of the worker 
 himself rather than to events outside his body, 
 although tins fact does not necessarily imply cul- 
 pability on his part. Thus of 2678 accidents in 
 Illinois in 1910 Bogardus (42) found that 82.2 per 
 cent represented those " in which loss of control, 
 varying from failure to make fine coordinations 
 on to gross and bungling coordinations and to 
 absence of movements which might have pre- 
 vented injury, appears to have been a factor." 
 In other words, most accidents have, in part, a 
 physiological origin. Of the various conceivable 
 physiological causes two, inexperience and fatigue, 
 are especially potent. 
 
 The Public Health Service (1) has found in one 
 73 
 
74 THE HUMAN MACHINE 
 
 of our factories a close parallelism between the 
 number of new employees engaged and the number 
 of accidents, and the results of the observations are 
 pictured in Fig. 8. The curves need no discussion. 
 The old and tried worker may become careless at 
 times and, while scorning danger, may fall into it; 
 but it is the inexperienced man who is the more 
 prone to injure himself — a strong argument against 
 a frequent change in the personnel of the workers. 
 Both keenness of attention and precision of 
 movement are impaired in fatigue. Bogardus 
 found by a simple laboratory experiment that un- 
 interrupted work is accompanied by increasing 
 muscular inaccuracy, a result that is indicative of 
 the participation of fatigue in the causation of in- 
 dustrial accidents. This is made very certain by 
 their hourly distribution throughout the working 
 day (6). Most of the tabulations that have been 
 made agree in showing that as output diminishes in 
 each spell, coincident with the progress of fatigue, 
 accidents increase in number — the curve grad- 
 ually rises through the spell (Fig. 9). The maxi- 
 mum number, however, usually occurs not at the 
 end of the spell, but some time before the end, 
 and during the final hour or more there is a diminu- 
 tion, the curve thus terminating with a fall. This 
 fall is usually ascribed partly to a diminution in the 
 number of workers, partly to their more leisurely 
 
INDUSTRIAL ACCIDENTS 75 
 
 Accidents 
 
 Net Inexperience 
 
 NOV. 
 
 DEC. 
 
 JAN. 
 
 FEB. 
 
 MAR. APR. 
 
 MAY 
 
 Fio. 8. — Parallelism of number of accidents and number of inex- 
 perienced employees in a large munition factory. (By cour- 
 tesy of the U. S. Public Health Service.) 
 
 LUNCH 
 
 9 10 11 12 1 
 
 Fia. 9. — Distribution of industrial accidents in the working day. 
 Total of many industries. (Ohio Industrial Commission, 
 Department of Investigation, Report No. 4, 1914.) 
 
76 THE HUMAN MACHINE 
 
 occupation, and partly to the fact that their ex- 
 pected release from labor quickens and makes more 
 precise the action of their neuromuscular mechan- 
 ism and thus diminishes the chances of a casualty 
 occurring. Whatever the explanation of the final 
 and usually brief fall in the curve, the main fact of 
 the progressive increase in accidents with pro- 
 gressive fatigue exists and is impressive. The 
 worker who is fresh at his work, keenly attentive, 
 and capable of making the proper motions and of 
 keeping out of harm's way may, it is true, inad- 
 vertently thrust his hand into the gears, or touch 
 the cutting tool, or step into the path of the hot 
 metal — accidents begin with the beginning of the 
 day's work — but the worker who is tired omits the 
 finer neuromuscular coordinations, makes the 
 grosser and more bungling movements, or alto- 
 gether neglects the things which physiologically he 
 ought to do — his fatigued condition is largely re- 
 sponsible for his mistakes. 
 
 Accidents are increased in number by poor illu- 
 mination. The British Departmental Committee 
 on Lighting in Factories and Workshops (43) has 
 found that accidents are far more numerous with 
 artificial than with natural lighting, rising in some 
 cases of the former 40 per cent above those of the 
 latter. This probably accounts chiefly for the 
 greater preponderance of industrial accidents in 
 
INDUSTRIAL ACCIDENTS 77 
 
 the winter as compared with the summer months, a 
 fact also pointed out by the Committee. 
 
 The greater number of accidents occurring dur- 
 ing night work than during day work has already 
 been mentioned (p. 68). It is not clear in how far 
 this difference is dependent upon the physical 
 condition of poorer illumination and in how far a 
 depressed physiological condition is responsible. 
 
 Accidents, however caused, are a serious bar to 
 the efficiency of the human machine, quite apart 
 from their direct pecuniary cost to the employer. 
 In proportion to the severity and in accordance 
 with the nature of their injuries injured workmen 
 lose time and productive power. If wholly in- 
 capacitated, whether permanently or not, their 
 places must be filled by others, and here produc- 
 tion is delayed by the necessary training. It is 
 obviously to the interest of the employer to reduce 
 the workers' injuries to their smallest possible 
 number, and the employer has it in his power to 
 prevent a large proportion of them. It must, 
 nevertheless, be recognized, I believe, that, how- 
 ever much employers may have a wholesome 
 regret for the occurrence of accidents to their 
 workers and however much they may realize the 
 expense caused thereby, many of the employers 
 fail to appreciate both the great wastefulness and 
 hindrance to production involved in such casual- 
 
78 THE HUMAN MACHINE 
 
 ties and the ease with which they may be dimin- 
 ished in number. One of the most obvious pre- 
 ventive measures is the installation of safety 
 devices, which are now numerous, varied, effective, 
 and often inexpensive. No really progressive 
 manager will neglect them. Whatever will reduce 
 the labor turnover will reduce accidents. But 
 the avoidance of excessive fatigue is of prime im- 
 portance, and this can be done by means of the 
 various provisions against fatigue that are here 
 advocated, such as not overdriving, allowing rest 
 pauses, shortening a long working period, and 
 other measures. 
 
XIII 
 
 INDUSTRIAL MEDICINE. WELFARE WORK 
 
 It goes without saying that an efficient body 
 must, in the long run, be a body free from disease. 
 In so far as the causes of disease lie in the condi- 
 tions of industrial work their existence has no jus- 
 tification, either ethical or economic; and yet an 
 examination of any of the excellent existing 
 treatises on industrial diseases (44) will make one 
 keenly aware of their great prominence in the life 
 of to-day. Here again fatigue must be recognized 
 as one of the chief factors. Several years ago, 
 while on a railway trip to one of our state capitals 
 for the purpose of opposing proposed unwise legis- 
 lative action against scientific medicine, a valued 
 friend of mine, one of the leading American path- 
 ologists, expressed to me his firm conviction that 
 in the course of time fatigue would be recognized 
 as one of the main causes of disease; and Sir 
 James Paget is quoted as writing " You will find 
 that fatigue has a larger share in the promotion 
 or transmission of disease than any other single 
 causal condition you can name." Here may be 
 
 79 
 
80 
 
 THE HUMAN MACHINE 
 
 mentioned an instructive research by Abbott and 
 Gildersleeve (45), who found that when rabbits 
 
 were inoculated with 
 pathogenic bacteria 
 and were then fa- 
 tigued by running 
 several hours each 
 day in a wheel they 
 died, while other 
 rabbits, inoculated, 
 but not fatigued, 
 survived. With the 
 fatigued rabbits the 
 opsonic index, which 
 may be interpreted 
 to the layman as 
 that condition of the 
 blood which signifies 
 the degree of sus- 
 ceptibility of the 
 organism to b a c - 
 terial infection, was 
 gradually reduced 
 as the fatigue pro- 
 gressed. Cessation 
 of the fatiguing process for even a day resulted in a 
 partial recovery of depression in the opsonic index 
 (Fig. 10). The bearing of such an experimental 
 
 o 
 
 - X 
 
 oS 
 o "" 
 
 -16 
 
 2/ 
 
 Ai 
 
 As 
 
 % 
 
 %0 
 
 Ki 
 
 /22 
 
 /23 
 
 »/& 
 
 2 A* 
 
 
 
 
 
 
 
 
 
 
 
 2.0 
 
 
 
 
 
 
 
 
 
 
 
 1.9 
 
 
 
 
 
 
 
 
 
 
 
 1.8 
 
 
 
 
 
 
 
 
 
 
 
 1.7 
 
 
 
 
 
 
 
 
 
 
 
 1.6 
 
 
 
 
 
 
 
 
 
 
 
 1.5 
 
 
 
 
 
 
 
 
 
 
 
 1.4 
 
 
 
 
 
 
 
 
 
 
 
 1.3 
 
 
 
 
 
 
 
 
 
 
 
 1.2 
 
 
 
 
 
 
 
 
 
 
 
 1.1 
 
 
 
 
 
 
 
 
 
 
 
 1.0 
 
 
 
 
 
 
 
 
 
 
 
 0.9 
 
 
 
 
 
 
 
 
 
 
 
 0.8 
 
 
 
 
 
 
 
 
 
 
 
 0.7 
 
 
 
 
 
 
 
 
 
 
 
 0.6 
 
 
 
 
 
 
 
 
 
 
 
 0.5 
 
 
 
 
 
 
 
 
 
 
 
 0.4 
 
 
 
 
 
 
 
 
 
 
 
 0.3 
 
 
 
 
 
 
 
 
 
 
 
 WEIGHT 
 
 i6oa 
 
 1590 
 
 1550 
 
 140O 
 
 
 1350 
 
 1350 
 
 1200 
 
 1220 
 
 HOURS 
 OF WORK 
 PER DAY 
 
 3-3 
 
 3-4 
 
 4-4 
 
 IESTE1 
 
 4-4 
 
 6 
 
 7-4 
 
 2 
 
 
 Fig. 10. — Effect of fatigue on the 
 opsonic index of a rabbit, (Ab- 
 bott and Gildersleeve.) 
 
INDUSTRIAL MEDICINE 81 
 
 result on the causation and the prevention of in- 
 fectious diseases in industrial work is sufficiently 
 obvious. The identification and treatment of 
 industrial diseases and the appreciation of indus- 
 trial hazards to health and ways of preventing 
 them, are parts of the general modern recognition 
 of the importance of the individual and the duties 
 of society toward him. Here the doctor, the phi- 
 lanthropist, and the legislator have worked in 
 helpful partnership, and the industrial employer 
 cannot afford to refuse his cooperation. 
 
 An additional word may be said of a specific 
 phase of these endeavors that has been coming 
 into prominence in recent years under the general 
 title of " welfare work." A recent writer (46) has 
 thus summarized its activities: "With reference 
 to the physical condition of the wage earners, wel- 
 fare work includes such things as good air and 
 light, lockers for clothing, dressing rooms, baths, 
 the provision of wholesome food for the midday 
 meal, rest-rooms for women, medical examina- 
 tions, first aid to the injured, free hospital beds, 
 visiting nurses, opportunities for organized ath- 
 letics, and vacations with pay. Under the head of 
 economic agencies it includes such things as shop 
 schools, technical lectures, and the circulation of 
 technical literature; prizes and bonuses for sug- 
 gestions, and for length and regularity of service; 
 
82 THE HUMAN MACHINE 
 
 sickness, accident, and old-age pensions; improved 
 housing facilities, and agencies for the promotion of 
 thrift. Upon general moral and social conditions 
 it exerts an influence, not only through the above- 
 mentioned channels, but by means of amusement 
 facilities, such as concerts and entertainments; 
 by clubs and societies; through the influence of a 
 social secretary; through the precautionary exclu- 
 sion of undesirable persons; and through the 
 agency of artistic surroundings, not only within 
 doors, but as the result of the landscaping of the 
 factory grounds." 
 
 Such a comprehensive program for human bet- 
 terment is commendable, and most, if not all, of its 
 features are practicable. The importance of wel- 
 fare work is now generally recognized, and it is 
 being gradually installed as an essential part of 
 industry. Its name " welfare work," is, I think, 
 somewhat unfortunate, for it contains an implica- 
 tion of a repellent excess of virtue. Its too zeal- 
 ous or too precipitate imposition upon an unwilling 
 body of employees has, at times, aroused opposi- 
 tion among them, and their lack of appreciation or 
 positive rejection of its benefits has, at times, led 
 employers to abandon it after a trial. But such 
 failures should not blind one to its real value. 
 Welfare work should not be too rapidly developed 
 in a factory; it should avoid arousing the suspicion 
 
INDUSTRIAL MEDICINE 83 
 
 that it is a gift, carrying with it the secret expec- 
 tation that it is to be paid for by increased pro- 
 duction; it should not seem too paternalistic; it 
 should not pry too much into the worker's private 
 life; it should not seem to be imposed upon the 
 worker; but it should be established and admin- 
 istered as a bond of mutual helpfulness between 
 employer and employee. 
 
 All bonds of such a nature, all things that lead 
 to the advancement of the health and content- 
 ment of the worker and promote his good will, 
 all these act as lubricants to the human machine 
 and are indispensable to its highest efficiency. 
 
XIV 
 
 FOOD 1 
 
 The human machine like other motors must be 
 supplied with fuel, and this should contain, in 
 latent form, at least the amount of energy that 
 is to be transformed, partly in the performance of 
 the work and partly in maintaining the heat of the 
 body. But unlike other motors, which require but 
 one kind of fuel, such as coal or gasoline, the 
 human machine can thrive best when it has various 
 kinds, and these are known as food-stuffs. While 
 there is considerable difference of opinion as to 
 the most advantageous proportion of human food- 
 stuffs a reasonable combination of the three main 
 varieties is that in which proteins supply about 
 15 per cent of the required energy, and fats and 
 carbohydrates the remainder, the carbohydrates 
 contributing much more energy than the fats. 
 Persons who are engaged in muscular activity 
 require more food than do those living a sedentary 
 life, and the added amount required is, in general, 
 proportional to the added amount of energy that 
 is expended; here the added amount can be sup- 
 plied best by added fats and carbohydrates, espe- 
 
 1 See Bibliography (47). 
 84 
 
FOOD 85 
 
 cially the latter. The relation between occu- 
 pation and fuel requirement is illustrated by the 
 following table which has been compiled from 
 various authorities (48). 
 
 Occupatic 
 
 Calories Source of calculations. 
 
 22.50 
 
 Clerk at desk 
 
 Sales clerk, machinery watcher, 
 
 house worker 2500 
 
 Light, muscular work 2S00 
 
 Carpenter, mason 3200 
 
 Farmer 3.500 
 
 Excavator 4000 Tiaerstedt 
 
 Atwater and Bryant 
 
 Lusk 
 
 Atwater and Bryant 
 
 Tigerstedt 
 
 Lusk 
 
 Probably most men working in munition factories 
 require a daily income of energy* measured by 
 3000-4000 heat-units, or calories, while the work- 
 ing woman's requirement is S0-90 per cent of that 
 amount or even less. 
 
 Mrs. Rose (49) has suggested the following day's 
 food plan for a working man doing severe work. 
 
 Fuel Requirement : 3500-4000 Calories. 
 
 Breakfast. caio™.. 
 Cereal (oatmeal, cornmeal, etc.; fried occasion- 
 ally) 150-300 
 
 Sausage, or salt fish, or liver and bacon 200-300 
 
 Toast, or muffins, or cornbread 300-400 
 
 Oleomargarine 150-300 
 
 Milk for cereal and coffee 100 
 
 Sugar for cereal and coffee 100 
 
 1000-1200 
 
86 THE HUMAN MACHINE 
 
 Luncheon. 
 
 Beans, peas or lentils (baked, or in soup or stew), 
 
 or macaroni and cheese, or cheese 200-400 
 
 Bread (rye, graham, white, etc.) 200-400 
 
 Fruit, fresh or as sauce (bananas, apples, apricots, 
 
 prunes) 100-150 
 
 Cake or pie 200-400 
 
 Milk and sugar for coffee 200 
 
 1000-1400 
 Dinner. 
 
 Meat pie, or stuffed meat and potatoes, or meat 
 
 stew with dumplings 300-400 
 
 Savory vegetable (onions, tomatoes or cabbage) . 100-200 
 
 Bread 200-400 
 
 Suet pudding, or bread pudding, or creamy rice 
 
 pudding 250-400 
 
 Milk and sugar for coffee 200 
 
 1400-1800 
 
 If the proper amount of fuel is not provided for 
 the human machine the proper amount of work is 
 not obtained from it in the long run — this result 
 is just as certain as it is with the non-living motor 
 — lack of fuel leads to fatigue and diminished pro- 
 duction. Moreover, it is not sufficient simply to 
 provide the proper amount, but it is imperative 
 that it be provided in a digestible state — indiges- 
 tion conduces to fatigue and thus helps to limit 
 output. It is thus directly advantageous to both 
 the employer and the worker that the latter be 
 
FOOD 87 
 
 properly fed. The worker is rarely acquainted 
 with scientific dietetics and, because of his lack of 
 knowledge of what constitutes a balanced ration, 
 of skill in buying, and of wise ways of cooking, if 
 left to his own judgment, he is more apt to be ill 
 fed than well fed. Here the employer can per- 
 form a real service. In attempting to reform the 
 worker's nutritive habits in his own home the 
 employer is, perhaps, limited to education and 
 the giving of advice, but at least one scientifi- 
 cally prepared meal can advantageously be 
 served to the workers at the factory. The rea- 
 sons for this are many. The American investiga- 
 tors (1) have found that a considerable proportion 
 of the workers in the munition factories come 
 to the plant in the morning without breakfast, 
 having risen early and perhaps travelled a 
 long distance, and then work through the first 
 spell without any food whatever. Restaurants in 
 the vicinity of a factory are apt to be inadequate 
 in size and equipment. Food brought from home 
 in a lunch box must be cold and is often ill bal- 
 anced from the nutritive standpoint. If the 
 worker's home is near enough to tempt him to go 
 to it, he cannot profitably do so if the greater part 
 of his time must be spent in travelling to and fro 
 and only a small remainder is left for a quick and 
 hence indigestible bolting of his food. These facts 
 
88 THE HUMAN MACHINE 
 
 have appealed to many progressive managers, and 
 the luncheon provided at the factory is now com- 
 mon. To secure the best results it should be 
 planned by a scientific dietitian, and every effort 
 should be made to enable the worker to secure a 
 perfectly balanced ration. Care should be ex- 
 pended in procuring the proper quality of foods 
 and in preparing them in an appetizing and diges- 
 tible form. They should be served in a dining- 
 room and not in the factory work rooms. Service 
 should be prompt, and probably the accepted 
 method of the cafeteria is best. Adequate time 
 should be allowed for eating. The prices charged 
 should be low enough to make it advantageous to 
 the worker to seek this meal rather than one from 
 neighboring restaurants or from his own lunch 
 box. If the employer feels that he must have a 
 pecuniary return from this addition to the worker's 
 comfort he should seek his profit from increased 
 production and a better maintenance of working 
 power, rather than directly from the sale of food 
 across the canteen counter. The British Com- 
 mittee has been much impressed by the good re- 
 sults following the establishment of industrial can- 
 teens. They say: " These benefits have been 
 direct and indirect. Among the former has been 
 a marked improvement in the health and physical 
 condition of the workers, a reduction in sickness, 
 
FOOD 89 
 
 less absence and broken time, less tendency to 
 alcoholism, and an increased efficiency and output; 
 among the latter has been a saving of the time of 
 the workman, a salutary though brief change from 
 the workshop, greater contentment, and a better 
 midday ventilation of the workshop." 
 
XV 
 
 SCIENTIFIC MANAGEMENT 
 
 The most promising method of promoting effi- 
 ciency that has acquired prominence in recent 
 years is that which is called commonly " scientific 
 management" (50) and frequently "efficiency engi- 
 neering; " an occasional name is " Taylorism," a 
 title that appears more often in the European 
 than the American literature. The method origi- 
 nated with the American, Frederick W. Taylor, 
 and has been gradually developed during the past 
 forty years. Over it there has been a heated con- 
 troversy, with fervid zealous advocates on the one 
 side, the more extreme even looking upon it almost 
 as a religion, and on the other bitter opponents. 
 Out of it has grown the new profession of the effi- 
 ciency engineer, the industrial engineer, or the 
 industrial counsellor, and the system has been in- 
 troduced into a considerable number of industrial 
 establishments in this country, which are said 
 (1915) to include some eighty different industries. 
 
 In both the principles and the practices of sci- 
 entific management there is much diversity; 
 nevertheless, certain features stand out promi- 
 
 90 
 
SCIENTIFIC MANAGEMENT 01 
 
 nently. In it specialization is carried to a high 
 degree. It requires a relatively large adminis- 
 trative staff, and the work is planned, even in its 
 minutest details, by this force. Endeavor is often 
 made to* secure only especially competent workers 
 and those specially adapted to the tasks to be per- 
 formed. A careful analysis of each task is made 
 and each worker is limited to a single opera- 
 tion. In performing it unnecessary motions are 
 omitted. A time study by a stop-watch is made 
 and the average time is determined by which com- 
 petent workmen can perform the operation. This 
 becomes the standard time for the operation, and 
 all workers are expected thereafter to conform to 
 it. Full and exact instructions are given for the 
 performance of the task in the manner desired. 
 Much attention is given to standardizing tools 
 and other equipment and adapting them exactly 
 to the work. By some system of wage bonuses 
 endeavor is made to induce the worker to speed 
 up to his maximum, and often he is penalized if 
 he falls below the standard set. By carefully 
 planned routing and scheduling the material to 
 be used is always at his hand, and no time is lost 
 needlessly in waiting for material or in passing 
 it on from one worker or department to the next. 
 The advocates of scientific management profess 
 loudly against fatiguing or exhausting the worker. 
 
92 THE HUMAN MACHINE 
 
 The results of the employment of scientific man- 
 agement on production are said to be remarkable. 
 While in a cotton factory production was increased 
 only 20 to 30 per cent, the increase in a factory 
 manufacturing certain special forms of machinery 
 was reported as 100 per cent, in a government 
 arsenal 150 per cent, in the process of brick- 
 laying 170 per cent, in a second machine factory 
 200 per cent, in the process of shovelling 268 per 
 cent, and in the handling of pig iron 280 per cent. 
 Mr. Taylor thinks that with scientific manage- 
 ment it is " safe and conservative to say that the 
 output of the individual workman has been, on the 
 average, doubled." 
 
 When one reads the glowing accounts of the 
 theories of scientific management and hears of 
 results like these mentioned the first effect is a 
 feeling of profound admiration for the manner in 
 which the system has been logically thought out, 
 urged upon the industrial world, and put into prac- 
 tice. Here, at last, seems to be the long-sought 
 method by which the trying problem of efficiency 
 is to be solved. It is only when one gains a more 
 intimate acquaintance with the differing theories 
 as promulgated by different leaders and with the 
 differing modes of application of the method does 
 the illusion of perfection become somewhat 
 dimmed, 
 
SCIENTIFIC MANAGEMENT 93 
 
 No two of the acknowledged leaders in scientific 
 management, Taylor, Gantt, Emerson and others, 
 agree upon its fundamental principles. More- 
 over, when the principles come to be put into 
 practice there is lacking the exactness which the 
 claim to be " scientific " would seem to require. 
 For example, in engaging workers and assigning 
 them to their tasks no specific and exact tests, 
 physiological or psychological, are used to deter- 
 mine the worker's fitness; the methods used are 
 not essentially different from the conventional 
 methods used in non-scientific shops. In making 
 time studies of a specific task for the purpose of 
 determining a standard time for its performance, 
 sometimes only the fastest workers are selected, 
 sometimes only the slowest, sometimes only the 
 average. Moreover, when time measurements 
 have been made by the stop-watch the so-called 
 " necessary " time for doing the task is calculated. 
 In making this calculation different methods ap- 
 pear to be followed: sometimes the average of all 
 the figures is used, sometimes the median, some- 
 times the most frequently recurring figure, some- 
 times the minimum; and sometimes the figures 
 obtained are arbitrarily manipulated to obtain 
 finally the " necessary " time. Allowances are 
 then made for various modifying factors, such as 
 necessary delays, machine breakdowns, possible 
 
94 THE HUMAN MACHINE 
 
 errors in observation, etc. — into all of which the 
 unmeasured judgment of the observer enters. 
 The resultant standard time represents thus a 
 combination of exact measurement and inexact 
 judgment, which may vary greatly with the per- 
 sonal equation of the observer. In setting tasks 
 adequate attention does not appear to be given 
 to the natural physiological differences of individ- 
 uals. In fixing rates of payment the current mar- 
 ket rate for the locality, instead of the expected 
 output or the expected degree of efficiency, is 
 usually taken as the basis, and there is rarely any 
 guarantee that the rate will not be cut if the wages 
 for the operation mount to an alarmingly high 
 figure. There appears to be no reliable evidence 
 that employees under scientific management are 
 overworked, nevertheless in deciding whether 
 fatigue is present, no exact tests are made — indeed, 
 the leaders, while talking much of fatigue, do not 
 appear to have any adequate knowledge of the 
 physiology of the phenomenon, as is illustrated 
 by the statement of one that " Fatigue is due to a 
 secretion in the blood." Furthermore, usually no 
 careful and adequate precautions are taken, such 
 as the introduction of resting periods, to avoid the 
 incidence of fatigue. Little or no consideration is 
 given to the length of the working period — one of 
 the leading prophets is reported indeed as saying 
 that this is a moral question! The practice of 
 
SCIENTIFIC MANAGEMENT 95 
 
 scientifically managed shops in the matter of 
 guarding the worker against the possibility of 
 injury by accidents does not appear to be essen- 
 tially different from that in other establishments. 
 Facts like these do not oblige us to condemn 
 scientific management as a whole, but they cannot 
 fail to cast doubts on the divinity of its prophets 
 and make one suspect that their claims concerning 
 the value of their principles are somewhat exag- 
 gerated. Thus, while scientific management is to 
 be highly commended for what it has accom- 
 plished in organizing the administration of indus- 
 try and in improving the material equipment with 
 which industry works, in its dealings with the 
 human machine it falls far short of an ideal. It 
 does not relieve the prevailing ignorance of the 
 human machine that is shown by the factory man- 
 agement, nor does it offer a panacea for the cor- 
 rection of evils that oppose the highest develop- 
 ment of human efficiency. It is, indeed, perhaps 
 the most important of all modern movements 
 that have as their object the general promotion 
 of industrial efficiency, but, like all specific systems 
 that attempt glowing reforms in human activity, 
 of which the history of medicine offers a succession 
 of instructive examples, it is, I believe, destined 
 to pass away as a system, while contributing what- 
 ever of good it possesses to the common stock of 
 agencies in industrial advance. 
 
XVI 
 
 THE PHYSIOLOGICAL ORGANIZATION OF WORK 
 
 There is one element, which has been men- 
 tioned in scientific management, that deserves 
 further consideration by us, namely, the analysis 
 of industrial operations from the physiological 
 standpoint. This analysis has usually been car- 
 ried on, especially by the followers of scientific 
 management, by means of simple ocular demon- 
 stration, a method that is obviously imperfect. 
 Gilbreth (11) improved this by using the cinemato- 
 graph with various mechanical devices added. 
 Several European physiologists have employed the 
 accepted methods of the physiological laboratory. 
 Among these are Imbert and Amar. Imbert and 
 Mestre (51) connected a loaded baggage truck to 
 tambours recording on a revolving drum and thus 
 obtained records of the motions involved in hand- 
 ling it (Fig. 11). In transporting sacks weighing 
 60 kilograms along a horizontal cemented ground 
 they found that in a ten-hour day the work of a 
 man would equal the sum of the following items: 
 
 1. A vertical ascent of 70 meters. 
 
 2. A horizontal course of about 30 kilometers. 
 
 96 
 
Fiu. 11.— Illustrating a method of physiological analysis of an 
 industrial operation. (Imbert and Mcstre.) 
 
ORGANIZATION OF WORK 97 
 
 3. The movement through these distances of a 
 total load of 18,600 kilograms by the muscles of 
 the arms. 
 
 They found further that the fatigue resulting 
 from one hour of this work is still far from being 
 dissipated by an absolute rest of two hours. They 
 think it entirely feasible to make the principle 
 of the method generally applicable to industrial 
 operations. 
 
 A mar (52) has placed tambours over the various 
 muscles and has recorded their contractions. He 
 has also registered the beats of the heart and the 
 movements of respiration, as to both rate and in- 
 tensity, and the amount of the gaseous exchange 
 in respiration. From the latter he has calculated 
 the energy expended. He has also made use of 
 the cinematograph. He has thus endeavored to 
 determine with a fair degree of mathematical ex- 
 actness for various fundamental operations the 
 physiological requisites for maximum production 
 with minimum fatigue, in other words, the most 
 economic physiological attributes of the work. 
 Thus, for the simple operation of filing metal he 
 finds that to obtain the best results in the filing 
 of brass with a half-round file, 35 centimeters in 
 length, the following conditions are essential: 
 
 The body of the subject should be vertical, without stiffness, 
 distant 20 cm. from the vise, and the latter at the height of 
 
98 THE HUMAN MACHINE 
 
 the navel; the position of the feet should be such that their 
 angle to one another should be 6S° and the distance between 
 the toes of the two feet 25 cm. ; the left arm should be com- 
 pletely extended and should bear down upon the tool a little 
 more heavily than the right arm — 8500 kg. and 7500 kg., 
 respectively. The return of the file should be by a simple 
 sliding motion, without any pressure from the arms; the 
 rhythm of the movement should be about 70 per minute. 
 With these conditions fulfilled, the operation should continue 
 five minutes and be followed by one minute of complete rest 
 during which the arms should hang at the sides of the body. 
 Respirations and heart beats, respectively, should not increase 
 more than 25 and 20 j>er cent in rate in comparison with their 
 figures at rest. The local fatigue of the forearm is then 
 endurable and general fatigue is hardly felt. Under these 
 conditions, the maximum work is at least twice that of most 
 workmen. In seven hours of such effective work 600 gin. 
 of brass filings -In mid be obtained. 
 
 This is the ideal physiological picture. Most work- 
 men do not attain it, but rather give a median 
 result with movements of fair regularity. With 
 the novice, however, the position of the body is 
 bad (Fig. 12), the muscular movements are irreg- 
 ular, awkward, badly directed, too intense, and 
 too sudden, and breathlessness and temporary 
 fatigue appear and require too early cessation of 
 the efforts (Figs. 13 and 14). Amar has similarly 
 analyzed the work of planing wood, transporting 
 burdens, such as the soldier's equipment on a level 
 and up an incline, bicycling, spading the earth, 
 wheeling a barrow, etc. 
 
Fig. 12. — Physiological comparison of the trained (left) and the 
 untrained (right) worker in the operation of filing. (From 
 Amar, Organisation Physiologique du Travail.) 
 
ORGANIZATION OF WORK 99 
 
 Such investigations as these offer an enticing 
 field of study for the physiologist. Their value in 
 demonstrating that ideals can be made realities 
 cannot be denied ; but it is impossible at present 
 to foretell their full utilitarian value. If, as some 
 of the followers of scientific management antici- 
 pate, specialization in industrialism is to be carried 
 to an extreme, if there are to be no skilled workers 
 in the future, if the unskilled mass can be trained 
 in a few minutes to perform the operation that is 
 to win the worker living wages and more, the more 
 exact methods of training would seem superfluous 
 and uneconomical. But, if, as many prophetic 
 thinkers maintain, there is still to be a place for 
 vocational education it can only be completely 
 satisfactory when it is placed on a sound physio- 
 logical basis, and in such case there is need of a 
 great extension of the physiological analysis and 
 organization of specific tasks. 
 
xvn 
 
 SUMMARY 
 
 What now are some of the conclusions that we 
 are justified in drawing from the present tendencies 
 of research concerning ways in which industrial 
 efficiency and productivity can be promoted? 
 The qualifications of prospective workers should 
 be determined so far as possible by exact tests, and 
 workers should be assigned to tasks in accordance 
 with their qualifications. A feeling of mutual con- 
 fidence should be established between the man- 
 agement and the worker, and nothing should be 
 done by either to destroy that feeling. The worker 
 should not wilfully limit his production, but should 
 work according to his capacity. Wages should be 
 adequate for work done, should enable the worker 
 to live decently, and once fixed should not be low- 
 ered if the worker is competent to earn the rate 
 agreed upon. The length of the working period 
 should tend toward a shortening rather than a 
 lengthening, and each of the two spells should be 
 broken by at least one recess period. The lunch- 
 eon recess should not be less than one-half hour, 
 
 100 
 
o<S(/7' / * / l^6 Jit^^lyL _ do4Lc£s 
 
 
 
 ■*fi*tr<]o*>*tf£~ Ktn**> 
 
 ^U^-oc^l. *te_ yCt 
 
 Q^^-f.tXft £**<^<»t+lo& *<>■ t~ <«°^ J*mtfi 
 
 /let4sl4*.a<M^"x4 
 
 m 
 
 I lIlVMtWII.i r.iiM 
 
 I'LHiMH^M^U'ak'kiAilliklkUk^ii 
 
 ^e***/"" &*c 4&c*,^M<f 
 
 Fig. 13. — Records oi physiological movements in the operation of filing 
 by an experienced worker. From above downward the successive 
 curves represent respectively: The vertical pressure of the two 
 
 hands; the vortical pressure of the left hand; the horizontal pressure 
 of the left hand; the horizontal pressure of the right hand; the respi- 
 ratory movements; the tune in seconds. (From Amar, Organisation 
 Physiologique du Travail.) 
 
c£t>J''fi £. &*-tm*' - *£<maaAj 
 
 ^Lj^tm »rev4.i«ic^*0 **«**: ^vk«^*4 
 
 fffffl^mi^iMBWamM 
 
 J^WtW<«M^ fTn^-ia^. <?6. &. ^vue**&. : 
 
 
 Grrr*f>trt*sx/Z. -£4^n*fa&^&^*^J*+&- 
 
 0At«/fw*-ot£<_o»v*& 
 
 O^ JU* <%«&•' 
 
 Fig. 14.— Records of physiological movements in the operation of filing 
 by an inexperienced worker. From above downward the succes- 
 sive curves represent respectively: The vertical pressure of the two 
 hands; the vertical pressure of the left hand; the horizontal pres- 
 sure of the left hand; the horizontal pressure of the right hand; the 
 respiratory movements; the time in seconds. (From Amar, Organi- 
 sation Physiologique du Travail.) 
 
SUMMARY 101 
 
 and one hour is preferable. If night work is neces- 
 sitated it should be confined to men only, and the 
 working night should not be longer than the work- 
 ing day. Exact records of the output of all indi- 
 vidual workers should be kept, where the nature 
 of the work makes it possible, and the effects on 
 output of changes in the working conditions should 
 be carefully observed. Constant watch should be 
 made, with the help of exact tests if possible, for 
 evidences of over-fatigue, and if they are found, 
 the conditions of labor for the individual should be 
 lightened. Overtime should be resorted to, if at 
 all, only in occasional emergencies, and should be 
 followed by at least an equal period of rest, taken 
 from the following day's work. Six working days 
 should be followed by one day of rest. Legal holi- 
 days should be strictly observed, and a half-holiday 
 on a week day is advisable. Women can be advan- 
 tageously employed for a large number and variety 
 of the operations that do not demand great mus- 
 cular strength, and they are especially efficient as 
 inspectors; they should not be given night work. 
 Any physical conditions of the shop, such as bad 
 lighting, poor ventilation, and excessive heat, that 
 conduce to fatigue, should be eliminated. Modern 
 sanitary provisions for the worker's comfort and 
 health should be maintained within the factory, 
 anc! rest rooms and, so far as practicable, chairs 
 
102 THE HUMAN MACHINE 
 
 should be provided for women. Safety devices 
 against the hazards of work should be main- 
 tained. If good restaurants, adequate in size, do 
 not exist near the factory, the company should 
 provide dining rooms where food, planned accord- 
 ing to the principles of modern scientific dietetics 
 and well cooked, can be had at cost prices for such 
 workers as do not live near the factory. The com- 
 pany should maintain at the factory a medical and 
 nursing staff, and should attend to all cases of 
 sickness or injury in which first aid is required. 
 If comfortable housing for the workers is not avail- 
 able, the company should devise plans by which it 
 may be had at reasonable prices. Employers 
 should have decent regard for the welfare of their 
 employees outside the factory, but should ' not 
 impose their attentions too autocratically. Work- 
 ers, once proved competent, should be retained, 
 and every effort should be made to secure a low 
 labor turnover. During the war emergency spe- 
 cial efforts should be made to stimulate the patriot- 
 ism of the workers, and they should be made to 
 realize that they individually have an important 
 part to play in the winning of the war and in help- 
 ing to establish in the world the rule of right and 
 justice. In so far as these conditions, formidable, 
 I will allow, in number and difficulty of attainment 
 but not impossible, can be established, industrial 
 
SUMMARY 103 
 
 efficiency will be by so much achieved, and the 
 ending of the war will be by bo much hastened. 
 
 It was only a few months ago that a clear-sighted 
 Frenchman (53) wrote: " A nation finds itself 
 to-day in danger of defeat, not because it does 
 not know how to fight, but because it does not 
 know how to manufacture." 
 
 The war will end, however, and industrial effort 
 will still continue. The principles which I have 
 here been presenting will, I trust, prove to be per- 
 tinent long after the war has ceased. 
 
 I cannot close this brief sketch without pointing 
 out what seems to me a close parallelism in their 
 historical development between medicine and in- 
 dustrialism. In both there is a conflict between 
 the old and the new, between empiricism and tra- 
 dition on the one side and science on the other. 
 In medicine in recent decades science has been 
 rapidly winning, and the chief single agency in this 
 victory has been the experimental method, the 
 method which more than all others characterizes 
 modern science. Industrialism is not so far ad- 
 vanced in its evolution as is medicine; it is still 
 lamentably under the control of empiricism and 
 tradition; but science is making progress here. 
 In this general industrial advance it is becoming 
 increasingly clear that in all that pertains to the 
 efficiency of the worker the physiological point of 
 
104 THE HUMAN MACHINE 
 
 view is the most helpful point of view. In our 
 analysis of the conditions of efficiency we always 
 come ultimately to the underlying fact that the 
 worker is a physiological mechanism and must be 
 treated as such. Here is the proper scientific 
 basis for the organization of industrial work. We 
 already have the promising beginnings of a science 
 of industrial physiology. What is needed now is a 
 great extension of the method of experiment, partly 
 in laboratories, but especially in factories, by which 
 facts may be accumulated, principles may be es- 
 tablished, and this new science may be rationally 
 developed. In this direction I believe that indus- 
 try has in America to-day an unparalleled oppor- 
 tunity for progress. 
 
BIBLIOGRAPHY 
 
 1. In the United States, the Public Health Ser- 
 vice has been conducting, since July, 1917, an in- 
 vestigation of the conditions of labor in certain of 
 the munition factories, for the purpose of discov- 
 ering whether excessive fatigue is present, how it 
 may be avoided, and how a continuous maximum 
 production of war supplies may be secured. The 
 work has been carried on with the active coop- 
 eration of the Divisional Committee on Industrial 
 Fatigue under the Advisory Commission of the 
 Council of National Defense. This Committee 
 has now been constituted also the Sub-committee 
 on Fatigue in Industrial Pursuits of the National 
 Research Council. The membership of the Divi- 
 sional Committee is as follows: 
 
 Thomas Darlington, Secretary Welfare Committee, American 
 Iron and Steel Institute, Chairman. 
 
 Frederic S. Lee, Professor of Physiology, Columbia Univer- 
 sity; Chairman of the Sub-committee on Fatigue in 
 Industrial Pursuits of the National Research Council; 
 Consulting Physiologist, Public Health Service; Execu- 
 tive Secretary. 
 
 Robert E. Chaddock, Associate Professor of Statistics, Colum- 
 bia University. 
 
 105 
 
106 THE HUMAN MACHINE 
 
 Raymond Dodge, Professor of Psychology, Wesleyan Uni- 
 versity. 
 
 David L. Edsall, Professor of Clinical Medicine, Harvard 
 Medical School. 
 
 P. Sargant Florence, Organizing Secretary of the Committee 
 of the British Association for the Advancement of Science 
 appointed to investigate Fatigue from the Economic 
 Standpoint; recently Investigator of Industrial Fatigue 
 under the British Health of Munition Workers Commit- 
 tee; Scientific Assistant (Supervising Field Investigator), 
 Public Health Service. 
 
 Josephine Goldmark, Publication Secretary, National Con- 
 sumers' League; Special Expert, Public Health Service. 
 
 Ernest G. Martin, Professor of Physiology, Leland Stanford 
 University; Scientific Assistant (Physiologist), Public 
 Health Service; Captain Sanitary Corps, U. S. A. 
 
 A. H. Ryan, Professor of Physiology, Tufts Medical College; 
 Scientific Assistant, Public Health Service. 
 
 J. W. Schereschewsky, Assistant Surgeon General, in Charge 
 of Division of Scientific Research, Public Health Service. 
 
 Ernest L. Scott, Associate in Physiology, Columbia Univer- 
 sity; Captain, Sanitary Corps, U. S. A. 
 
 Of the many data which have been accumulated 
 by the Public Health Service in the above investi- 
 gation and are quoted in the present text few have 
 yet appeared in print. They are here made public 
 by the courtesy of the Service. Full reports of the 
 investigation will ultimately be published by the 
 Service. The Divisional Committee has published 
 (1918) a pamphlet entitled " How Industrial Fa- 
 tigue May be Reduced," which constitutes No. 1 
 of the Welfare Work Series issued by the Com- 
 
BIBLIOGRAPHY 107 
 
 mittee on Labor under the Advisory Commission 
 of the Council of National Defense. 
 
 2. In Great Britain, the Health of Munition 
 Workers Committee, under the Ministry of Muni- 
 tions, has conducted, since September, 1915, an 
 investigation of the conditions of labor in munition 
 factories. The following reports of this work have 
 been published : 
 
 Memorandum 
 
 No. 
 
 1. Report on Sunday Labour. 1915. 
 
 2. Welfare Supervision. 1915. 
 
 3. Report on Industrial Canteens. 1915. 
 
 4. Employment of Women. 1916. 
 
 5. Hours of Work. 1916. 
 
 6. Canteen Construction and Equipment. 1916. 
 
 7. Industrial Fatigue and its Causes. 1916. 
 
 8. Special Industrial Diseases. 1916. 
 
 9. Ventilation and Lighting of Munition Factories and 
 
 Workshops. 1916. 
 
 10. Sickness and Injury. 1916. 
 
 11. Investigation of Workers' Food and Suggestions as to 
 
 Dietary. 1916. 
 
 12. Statistical Information Concerning Output in Rela- 
 
 tion to Hours of Work. 1916. 
 
 13. Juvenile Employment. 1916. 
 
 14. Washing Facilities and Baths. 1916. 
 
 15. The Effect of Industrial Conditions upon Eyesight. 
 
 1916. 
 
 16. Medical Certificates for Munition Workers. 1917. 
 
 17. Health and Welfare of Munition Workers Outside 
 
 the Factory. 1917. 
 
 18. Further Statistical Information Concerning Output 
 
 in Relation to Hours of Work, with Special Refer- 
 ence to the Influence of Sunday Labour. 1917. 
 
108 THE HUMAN MACHINE 
 
 Memorandum 
 No. 
 
 19. Investigation of Workers' Food and Suggestions as 
 
 to Dietary. Revised Edition. 1917. 
 
 20. Weekly Hours of Employment. 1917. 
 
 21. An Investigation of the Factors Concerned in the 
 
 Causation of Industrial Accidents. 1918. 
 Interim Report. Industrial Efficiency and Fatigue. 
 
 1917. 
 Health of the Munition Worker. Handbook Prepared 
 
 by the Health of Munition Workers Committee. 
 
 1917. 
 
 Some of these reports have been reprinted by 
 the U. S. Department of Labor as follows: 
 
 Memorandum 
 
 Nos. 
 
 1, 5, 7, 8, 9, 10, 12 and 15 in Bulletin of the United States 
 
 Bureau of Labor Statistics, No. 221, entitled 
 " Hours, Fatigue and Health in British Munition 
 Factories." 1917. 
 
 2, 3, 6, 11 and 14 in Bulletin of the United States Bureau 
 
 of Labor Statistics, No. 222, entitled "Welfare 
 Work in British Munition Factories." 1917. 
 4 and 13 in Bulletin of the United States Bureau of Labor 
 Statistics, No. 223, entitled "The Employment of 
 Women and Juveniles in Great Britain during the 
 War." 1917. 
 
 A summary of the reports has been published as 
 follows : 
 
 Walter: Munition Workers in England and France. New 
 York, Russell Sage Foundation, 1917. 
 
 3. Miinsterberg: Psychology and Industrial Efficiency. 
 Boston, 1913. 
 
BIBLIOGRAPHY 109 
 
 4. Hollingworth : Vocational Psychology, its Problems and 
 Methods. New York, 1916. 
 
 5. Lovett and Martin: The Spring Balance Muscle Test. 
 American Journal of Orthopedic Surgery, XIV, 415, 1910. 
 See also Martin and Rich: American Journal of Physiology, 
 XLVII, 1918; Mosher and Martin: Journal of the Ameri- 
 can Medical Association, LXX, 1918. 
 
 6. Florence: Use of Factory Statistics in the Investiga- 
 tion of Industrial Fatigue. A Manual for Field Research. 
 Columbia University. New York, 1918. 
 
 British Association for the Advancement of Science: The 
 Question of Fatigue from the Economic Standpoint. Interim 
 Report of the Committee, consisting of Professor J. H. 
 Muirhead (Chairman), Miss B. L. Hutchins (Secretary), 
 Mr. P. Sargant Florence (Organizing Secretary), et at. Pro- 
 ceedings of the British Association for the Advancement of 
 Science, p. 283, 1915. Second Interim Report, Do., p. 251, 
 1916. 
 
 7. Ryan: The Quantitative Measurement of General 
 Fatigue. Proceedings of the American Physiological Society, 
 American Journal of Physiology, XLV, 537, 1918. 
 
 8. Kent: Interim Report on an Investigation of Industrial 
 Fatigue by Physiological Methods. London, 1915. Second 
 Interim Report, Do. London, 1916. 
 
 9. The literature of fatigue is very voluminous. For brief 
 reviews of the physiological aspect of the subject the follow- 
 ing papers may be consulted: 
 
 Lee: Fatigue. Journal of the American Medical Associa- 
 tion, XLVI, 1491, 1906. Do. Harvey Lectures, 1905-06. 
 Philadelphia, 1906. 
 
 Lee: The Nature of Fatigue. Popular Science Monthly, 
 LXXVI, 182, 1910. 
 
 Lee and Aronovitch: Does a Fatigue Toxin Exist? Pro- 
 ceedings of the Society for Experimental Biology and Medi- 
 cine, XIV, 153, 1917. 
 
110 THE HUMAN MACHINE 
 
 The industrial aspect of fatigue is presented compre- 
 hensively in: 
 
 Goldmark: Fatigue and Efficiency. New York, 1912. 
 
 10. Gilbreth: Motion Study. New York, 1911. 
 
 11. Gilbreth and Gilbreth: Fatigue Study. New York, 
 1916. 
 
 12. Lee: The Effects of Temperature and Humidity on 
 Fatigue. American Journal of Public Health, II, 863, 1912. 
 
 Winslow, Kimball, Lee, Miller, Phelps, Thorndike and Pal- 
 mer: Some Results of the First Year's Work of the New 
 York State Commission on Ventilation. American Journal 
 of Public Health, V, 85, 1915. The full report of the Com- 
 mission has not yet been published. 
 
 13. Lee and Scott: The Action of Temperature and Humid- 
 ity on the Working Power of Muscles and the Sugar of the 
 Blood. American Journal of Physiology, XL, 486, 1916. 
 
 14. Lee: Fresh Air. Popular Science Monthly, LXXXIV, 
 313, 1914. 
 
 15. Taylor: The Principles of Scientific Management. 
 New York and London, 1911. 
 
 16. Lee: Is the Eight-Hour Working-Day Rational? 
 Science, XLIV, 727, 1916. 
 
 17. Mather: The Forty-eight Hours' Week; a Year's 
 Experience and Its Results at the Salford Iron Works, 
 Manchester. Manchester, 1894. 
 
 18. Fromont: Une Experience Industrielle de Reduction 
 de la Journ£e de Travail. Instituts Solvay. Brussels and 
 Leipzig, 1906. 
 
 19. Abbe: Die Volkswirtshaftliche Bedeutung der Ver- 
 kiirzung des Industriellen Arbeitstages. Gesammelte Ab- 
 handlungen, III, 203. Jena, 1906. 
 
 20. Fitch: Hours and Output; Some War-time Testi- 
 mony in Favor of a Short Work-day. The Survey, XXXVIII, 
 138, 1917. 
 
 21. Health of Munition Workers Committee: Further 
 Statistical Information Concerning Output in Relation to 
 
BIBLIOGRAPHY 111 
 
 Hours of Work, with Special Reference to the Influence of 
 Sunday Labour. Memorandum No. IS. London, 1917. 
 Health of the Munition Worker. London, 1918. 
 
 22. James: The Energies of Men. New York, 190S. 
 
 23. Martin, Withington and Putnam: Variations in the 
 Sensory Threshold for Faradic Stimulation for Normal Human 
 Subjects. 3. The Influence of General Fatigue. American 
 Journal of Physiology, XXXIV, 97, 1914. 
 
 24. Kent: The Monday Effect in Industry. Proceedings 
 of the Physiological Society, Journal of Physiology, L, lv, 
 1915-16. 
 
 25. Ayres: Music's Effect on Six-day Cyclists. Bicycling 
 World and Motorcycle Review. 1911. 
 
 26. Mosso: Fatigue. New York, 1904. 
 
 27. Hayhurst : Report of the Illinois Commission on Occu- 
 pational Diseases, 49, 1911. 
 
 28. Alexander: Cost of Labor Turnover. Proceedings 
 of the Employment Managers' Conference, Philadelphia, Pa., 
 April 2 and 3, 1917. Bulletin of the United States Bureau of 
 Labor Statistics, No. 227. Washington, 1917. 
 
 29. Andrews: Economic Effects of the War upon Women 
 and Children in Great Britain. New York, 1918. 
 
 30. Thompson: The Mental Traits of Sex. Chicago, 1903. 
 
 31. Weinberg: Krankheit und Soziale Lage. Der Ein- 
 fluss der Sozialen Lage auf Krankheit und Sterblichkeit der 
 Frau. Berlin, 1913. 
 
 32. Layet: Le Travail des Enfants et des Femmes dans 
 l'lndustrie. Encyclopeclie d'Hygiene et de M<klecine Pub- 
 lique, VI. Paris, 1894. 
 
 33. Warren and Sydenstricker: Health Insurance; its 
 Relation to the Public Health. Public Health Bulletin, No. 
 76. Washington, 1916. 
 
 34. Hollingworth : Functional Periodicity. An Experi- 
 mental Study of the Mental and Motor Abilities of Women 
 during Menstruation. New York, 1914. 
 
 35. Simpson and Galbraith: Observations on the Normal 
 
112 THE HUMAN MACHINE 
 
 Temperature of the Monkey and its Diurnal Variation, and 
 on the Effect of Changes in the Daily Routine on this Varia- 
 tion. Transactions of the Royal Society of Edinburgh, XLV, 
 65, 1905. 
 
 36. Linhard: Report of the Danish Expedition to the 
 Northeast Coast of Greenland, 1906-8, XLIV. Copenhagen, 
 1910. 
 
 37. Benedict: Studies in Body Temperature. 1. Influ- 
 ence of the Inversion of the Daily Routine; the Temperature 
 of Night-workers. American Journal of Physiology, XI, 
 145, 1904. 
 
 38. Health of Munition Workers Committee: Industrial 
 Efficiency and Fatigue. Interim Report. London, 1917. 
 
 39. U. S. Department of Labor: Accidents and Accident 
 Prevention. Report on Conditions of Employment in the 
 Iron and Steel Industry in the United States, IV. Senate 
 Document No. 110, 62d Congress. Washington, 1913. 
 
 40. New York State Factory Investigating Commission: 
 Night-work of Women in Factories. Second Report of 
 Commission, I, 1913. 
 
 41. Brandeis and Goldmark: The Case Against Night- 
 work for Women. National Consumers' League. New 
 York, 1918. 
 
 42. Bogardus : The Relation of Fatigue to Industrial Acci- 
 dents. American Journal of Sociology, XVII, 1912. 
 
 43. Departmental Committee on Lighting in Factories and 
 Workshops. First Report, I. London, 1915. 
 
 44. Kober and Hanson: Diseases of Occupation and Voca- 
 tional Hygiene. Philadelphia, 1916. 
 
 Thompson: The Occupational Diseases: Their Causation, 
 Symptoms, Treatment and Prevention. New York, 1914. 
 
 45. Abbott and Gildersleeve : The Influence of Muscular 
 Fatigue and of Alcohol upon Certain of the Normal Defences. 
 University of Pennsylvania Medical Bulletin, XXIII, 169, 
 1910. 
 
 46. Jones: The Administration of Industrial Enterprises. 
 
BIBLIOGRAPHY 113 
 
 New York and London, 1917. See also Tolman: Social 
 Engineering. New York, 1909. 
 
 47. Lusk: The Fundamental Basis of Nutrition. New 
 Haven, 1914. 
 
 48. Stern and Spitz: Food for the Worker. Boston, 1917. 
 
 49. Rose: Feeding the Family. New York, 1917. 
 
 50. Of the voluminous literature of Scientific Management, 
 the reader may profitably consult the following books: 
 
 . Taylor: The Principles of Scientific Management. New 
 York and London, 1911. 
 
 Gantt: Work, Wages and Profits. New York, 1913. 
 
 Emerson: Efficiency as a Basis for Operation and Wages. 
 New York, 1914. 
 
 Thompson: Scientific Management, A Collection of the 
 More Significant Articles Describing the Taylor System of 
 Management. Cambridge, 1914. 
 
 Drury: Scientific Management, A History and Criticism. 
 Columbia University. New York, 1915. 
 
 Hoxie: Scientific Management and Labor. New York 
 and London, 1916. 
 
 51. "Imbert and M6stre: Travaux Originaux des Inspec- 
 teurs. Recherches sur la Manoeuvre du Cabrouet et la 
 Fatigue qui en Resulte. Bulletin de l'lnspection du Travail, 
 XIII and XIV, 374, 1905. 
 
 Imbert: Les M^thodes du Laboratoire Appliqu&s a 
 l'Etude Directe et Pratique des Questions Ouvrieres. Revue 
 G£n6rale des Sciences Pures et Appliqu6es, XXII, 47S, 1911. 
 
 52. Amar: Organisation Physiologique du Travail. Paris 
 (Dunod & Pinat), 1916. 
 
 53. Hamp: La France Pays Ouvrier. Paris, 1916. 
 
 54. National Industrial Conference Board: Hours of 
 Work as Related to Output and Health of Workers, Cotton 
 Manufacturing. Research Report Number 4. Do., Boot 
 and Shoe Industry, Research Report Number 7, Boston, 191S. 
 
INDEX 
 
 Abbott and Gildersleevc, 80 
 
 Accidents, ":?: and fatigue, 74, 78; hourly distribution of, 74; 
 
 and illumination, 70; and inexperience, 74; and night 
 
 work, 68, 77 
 Acidosis, 16 
 Age of workers, 47 
 Alexander, 49, 50 
 Amar, 97 
 
 Bogardus, 73, 74 
 
 Ca' canny, 39 
 Capacity and output, 39 
 Chaney, 68 
 
 Day work compared with night work, 61 
 
 Efficiency, conditions of, 4 
 Efficiency engineering, 90 
 Eight-hour day, 27, 31, 36 
 Emerson, 93 
 Employers, duties of, 42 
 Engis Chemical Works, 33 
 Epstean, 59 
 
 Fatigue, and accidents, 74, 78; and age, 48; and composition 
 of urine, 16; and hearing, 15; and heat and humidity, 21; 
 and illumination, 21; and infection, 80; and luncheon, 
 25; and mental influences, 44; and monotonous work, 
 18; of muscle, 13, 24; in muscular work, 16; and music, 
 115 
 
116 INDEX 
 
 45; and output, 10; primary and secondary sources of, 
 19; and rest, 24, 45; and sight, 15, 46; and strength, 14; 
 tests for, 14; and ventilation, 21; weekly, 43 
 
 Fatigue substances, 24 
 
 Filing, physiological analysis of, 97 
 
 Food, 22, 84 
 
 Gantt, 93 
 Gilbreth, 19, 96 
 Greenwood, 67 
 
 Hamp, 103 
 
 Hastings, 16 
 
 Haynurst, 47 
 
 Health of Munition Workers Committee, 34, 45, 47, 67, 71, 88 
 
 Hearing and fatigue, 15 
 
 Heat and fatigue, 21 
 
 Hollingworth, 7, 58 
 
 Human machine, 2, 29, 104 
 
 Humidity and fatigue, 21 
 
 Illumination, and accidents, 76; and fatigue, 21 
 
 Imbert and Mestre, 96 
 
 Industrial medicine, 79 
 
 Industrial operations, repetitive, 10; variety of, 5 
 
 Industry, and medicine, 103; and physiology, 3, 4, 104; and 
 
 war, 3 
 Infection and fatigue, 80 
 
 James, 39 
 Jones, 81 
 
 Kent, 15, 43, 46 
 
 Labor turnover, 49 
 Lee, 21 
 
INDEX 117 
 
 Lovett and Martin, 8, 14 
 Luncheon and fatigue, 25 
 
 Machinery, 1 
 
 Martin, 8, 14, 43 
 
 Medicine, industrial, 79; and industrialism, 103 
 
 Menstruation, 58 
 
 Mental influences and fatigue, 44 
 
 Monday effect, 43 
 
 Monotonous work and fatigue, 18 
 
 Mosso, 46 
 
 Miinsterberg, 6 
 
 Muscle, fatigue of. 13, 24 
 
 Muscular work and fatigue, 16 
 
 Music and fatigue, 4.5 
 
 National Industrial Conference Board, 38 
 
 Night work, 61; and accidents, 68, 77; alternation with day 
 
 work, 71 ; efficiency of, 67; and health, 68; output of, 64; 
 
 and sleep, 70 
 
 Opsonic index and fatigue, 80 
 
 Output, and capacity, 39; curves of, 12, 17, 65; of day work, 
 
 11; and fatigue, 10; limiting of, 39; of night work, 66; 
 
 and scientific management, 92; stereotyping of, 40 
 Overtime, 46 
 
 Paget, 79 
 
 Physiological organization of work, 96 
 Physiology and industry, 3, 4, 104 
 Piece-rate, effect of cutting, 41 
 " Practical " point of view, 3 
 Practice effect, 14, 44 
 
 Public Health Service, 8, 10, 15, 16, 21, 27, 40, 50, 58, 64, 
 72,87 
 
118 INDEX 
 
 Rate setting, 42 
 Repetitive operations, 10 
 Rest and fatigue, 24, 45 
 Resting periods, 24 
 Rose, 85 
 Ryan, 15 
 
 Salford Iron Works, 32 
 
 Scientific management, 90 
 
 Scott, 21 
 
 Secondary sources of fatigue, 19 
 
 Shoe manufacture, 33 
 
 Sight and fatigue, 15, 46 
 
 Sleep and night work, 70 
 
 Soldiering, 39 
 
 Spring balance test, 8, 14 
 
 Strength, and fatigue, 14; standard, 8 
 
 Sunday work, 47 
 
 Taylor, 25, 90, 92, 93 
 
 Taylorism, 90 
 
 Temperature of body, 62 
 
 Tests, for fatigue, 14; for vocational fitness, 6 
 
 Thompson, 54 
 
 Trench-digging, 27 
 
 Treppe, 13 
 
 Vascular skin reaction test, 15 
 Ventilation and fatigue, 21 
 Vernon, 28, 34, 68 
 
 War and industry, 3 
 
 Welfare work, 81 
 
 Women, absences of, from work, 58; differences between 
 men and, 54; health of, 57; increase in employment of, 
 53; industrial efficiency of, 53; and night work, 70, 72 
 
INDEX 119 
 
 Workers, age of, 47; duties of, 4, 42; qualifications of, 5 
 Working day, effect of shortening, 31; length of, 29 
 Working power, maintenance of, 43 
 
 Zeiss Optical Works, 33