EXPLANATORY NOTES
SECTION II*
IV. EXPLANATORY NOTES AND DEVELOPMENT OF FORMULAE
The basic data and material used in this study are from the sourcesstated in the reference list. Much of the material is from the unpublishedstatistical tables and sheets on file in the office of the Surgeon General,which are referred to in the list. New tabulations were made from the statisticalcards to show how many cases left sick report during the first seven days,the second seven, etc., during the World War, as follows:
1. All cases wounded by gunshot missiles, and all deaths and disabilitydischarges resulting therefrom.
2. All cases wounded by poisonous gases, and all deaths and disabilitydischarges resulting therefrom.
3. (a) A sample of approximately 150,000 out of about 450,000 diseaseand nonbattle injury cases in the American Expeditionary Forces duringthe last six months of 1918. The sample included the. same proportion ofeach diagnosis.
(b) All of the deaths from diseases and nonbattleinjuries in the American Expeditionary Forces during 1918.
4. All deaths and discharges for disability among troops in the UnitedStates during 1918.
The task of tabulating a sufficiently large sample of the duty casesin the United States during 1918 was too great a one to be undertaken withthe time and personnel available. Similar data were available, however,for the troops in the United States during 1925-1927, and it was assumedthat there was no material difference in the duration of treatment of suchcases and of similar ones during 1918. Consequently those data availablefor the 1925-1927 cases were used as 1918 experience with the necessaryslight modifications as indicated in Figs. 80 and 82. In the absence ofmore exact information, estimates were used in some instances, as notedin the appropriate places. Whenever this was done all available data werechecked to test the estimated results.
*Section II is intended for use by only such as are interestedin the technical details in the development of the material in SectionI.
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The sources of information, the method of arriving at such estimateswere used, and the changes which were made in the basic data are notedin connection with the various Figures.
53. Patients leaving sick report. - The data for Figs. 21-64are largely from formulae. Figs. 79-98 inclusive. show the method of developingthem. The basic material as tabulated, shows how many patients of the duty,death, or disability groups left sick report during the first second, thirdweek, etc. The numbers leaving sick report each week were divided by thetotal in thousands to reduce each weeks cases to proportional parts per1000 of the total number.
54. Graduation of material. - In some instances attempts weremade to fit this basic material to second or third order parabolas andalso to Pearsonian curves, but the results were not satisfactory. It soonbecame apparent that there was a very definite geometrical progressionrelationship between the groups of cases leaving sick report by time intervalsor remaining on it, and that all of the curves were exponential in character.Inspection showed that this type of curve fitted the observed points quitewell with only a few exceptions. The apparent failure to fit was due usuallyto imperfections in, or incompleteness of, the basic material; but in someinstances, the necessity of relating the graduated data to those from othercurves resulted in the use of a poorer fit than could have been obtainedotherwise.
The exponential curve not only best fitted the observed points, butit graduated also satisfactorily the grouped experience beyond the 14thor 20th week; i.e., the limits of the tabulations by weeks.
55. Patients remaining on sick report. - During the early stagesof this work, the data for leaving hospital, or sick report, were firstsmoothed by fitting them to an exponential curve; but after a short timeit was found that as satisfactory results, could be obtained by omittingthat step and passing directly from the ungraduated, Leaving tothe ungraduated Remaining.
To find the number of patients from an original 1000 remaining sickat the end of the first week, either the graduated, or ungraduated, numberleaving was deducted from 1000. From the remainder so obtained, the numberleaving during the second week was subtracted to find the number remainingat the end of that time. This process was continued through the 14th, andin some instances through the 20th week. As stated, the number remainingbeyond that time was ultimately distributed by the formulae obtained.
The following table shows the general methods of handling the materialand the results obtained in this instance.
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Table 29. - Number of patientsamong white enlisted men in the United States. 1925-1927, inclusive, leavingsick report during each week, and also the number remaining on sick reportat end of each week.
(1) Weeks | Patients leaving sick report during each weekof treatment. | Patients remaining on sick report at end of eachweek of treatment. | |||
(2) | Per 1000 patients | Per 1000 patients | |||
(3) | (4) | (5) | (6) | ||
0 | 0 | 0 | 0 | 1,000.00 | 1,000.00 |
1. | 92010 | 531.61 | 531.61 | 468.39 | 468.39 |
2. | 33293 | 192.36 | 186.51 | 281.88 | 287.37 |
3. | 15192 | 87.78 | 90.05 | 191.83 | 191.86 |
4. | 8721 | 50.39 | 52.50 | 139.33 | 136.78 |
5. | 5723 | 33.07 | 33.50 | 105.83 | 103.30 |
6. | 3888 | 22.46 | 22.46 | 83.37 | 81.73 |
7. | 2958 | 17.09 | 15.79 | 67.58 | 66.89 |
8. | 2009 | 11.61 | 11.53 | 56.05 | 56.05 |
9. | 1456 | 8.41 | 8.74 | 47.31 | 47.69 |
10. | 1187 | 6.86 | 6.86 | 40.45 | 40.97 |
11. | 886 | 5.12 | 5.54 | 34.91 | 35.41 |
12. | 676 | 3.91 | 4.58 | 30.33 | 30.72 |
13. | 622 | 3.59 | 3.86 | 26.47 | 26.71 |
14. | 532 | 3.07 | 3.29 | 23.18 | 23.25 |
Over | 2922 | 22.66 | 23.18 | ||
Total | 173075 | 1000.00 | 1000.00 | ||
56. Exponential curve. - a. One section curve. - The basicformula of the exponential curve used was
y = ea+bx
In graduating the Leaving material, Y1designates the number of patients leaving during each week (X7); and likewise in graduating the Remaining data, Yrequals the number of patients remaining at the end of each week (X7).Where X represents a period of one week, or seven days, it is written X7;and where it represents a five day period, X5.
The basic ungraduated data were first plotted on arithmetic logarithmicpaper, as is shown by Fig. 79. In some instances where the material washomogenous, as with cases wounded by poisonous gases or by gunshot missiles(See Figs. 87 and 88), a one section curve was sufficient.
b. Two section curve. - In another class of cases, such as hospitalcases of disease and nonbattle injury patients, certain ones like compoundfractures of the femur and pulmonary tuberculosis which required prolongedtreatment, were not in the proper proportion to those needing only a fewdays in hospital to permit of a fit by a one section curve. In such instancesthere were relatively more short than long duration cases, and a two sectioncurve was required with the general formula
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yr=ea1+b1x7+ea2+b2x7
The sub 1 and sub 2 appended to the a and b designate the first (1)and second (2) section of the curve (See Fig. 82).
c. Three section curve. - In a third class of cases; such asthose of patients treated in hospital and quarters in the United Statesin 1925-1927, the short duration treatment ones, such as the majority ofthose in quarters, were relatively so much more numerous than the mediumand long duration cases, that a three section curve was required with thegeneral formula (See Fig. 80)
yr=ea1+b1x7+ea2+b2x7+ea3+b3x7
d. Plus and minus section curve. - In a few instances where therewas too large a proportion of long duration cases for the short durationones, it was found necessary to use a two section curve with the second,a minus one. Here the formula was
yr=ea1+b1x7-ea2+b2x7
e. Method of fitting. - In fitting the two or three section curves,the second or third section, as the case might be, with the long durationcases and the proper proportion of medium and short duration ones, wasfitted first. For this purpose, the observed data were plotted on, arithlogpaper, and a straight line was drawn through the lower end of the material.The angle of this line was determined by its fit of the observed pointsin that section, and also by the apparent accuracy of the graduation ofthe grouped material beyond the end of the available tabulation. This latterpoint was tested by comparing the total of the graduated and ungraduatedmaterial beyond the end of the available tabulation; and also by a carefulcheck against the detail of the basic data, which although scattered andirregular, showed quite definitely the general trend and time limits oftreatment.
The material so graduated was next subtracted from the ungraduated total.The remainder was then plotted on the same sheet of arithmetic log paper,and the second or first sections fitted. In every instance, a number oftrials was necessary before a satisfactory fit was obtained.
The sum of the different sections as graduated was summated by additionsor subtractions, as required, and the graduated total compared with theungraduated one.
In order to hold the higher points fixed, the fitting was by selectedpoints rather than by the least square method. The points used for fitting
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were usually two observed ones for each section; but in some instanceswhere the graph or trial showed that it was necessary, the points usedwere selected rather than observed.
f. Normal equation. - The normal equation used was log to base eof b of the equation
y = ea+bxor loge y=a+bx
The value of each x chosen with the loge of its correspondingy was substituted in two equations, which were then solved for aand b. This gave a formula of the general form
y = ea+bxor y=ea(ebx)
Here ea represents the original height of the curve; andeb the numerical value of the ratio between the height at anytime (x) and that of the next following it, or in other words, the slopeof the curve. The y then is a function of x, and varies as x varies.
g. Illustration of use of formula. - In illustrating the methodof developing the specific formulae, in the interest of simplicity theformula of a one section curve will be used. Thus the formula in Fig. 87,showing the number of gas cases remaining in hospital at the end of eachweek, is
yr=1000.00(.842250)x7
The 1000.00 is the ea; and the .842250, the eb.The curve then starts with 1000.00 patients of whom .842250 × 1000,or 842.25, are remaining in hospital at the end of one week (X7); and then of this remaining group (842.25) the same fraction (.842250)or 842.25 × .842250 = 709.39 are remaining at the end of the twoweeks, etc.
h. Change in size of basic group and time interval. - To convertthe formula into terms of 1 patient, simply divide by 1000 and then
yr=1.00(.842250)x7
The ebx is in terms of seven day periods. To convert it intoterms of one day (ebx1) take the seventh root ofit; and then to change the result into terms of any other period, as, forexample, a five day one (ebx5) as used here, raiseit to the fifth power.
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Thus from the above.
x5=antilogof 5(log .842250/7)=.884593
Then the formula by 5-day periods is
yr=1.00(.884593)x5
Yr, then is the number of patients remaining in hospitalat the end of successive five day periods. If, however, it is necessaryto find directly the fraction of a patient remaining at the end of anyother period, as for example one year (365 days), multiply as above bythat number instead of by 5.
Thus x365=antilogof 365 (log .842250/7)=.000130
If the ea is 1.00, on the 365th day, .000130 of 1 patientwill, still be in hospital; but if the ea is 1000.00, therewill be .13 (See Fig. 87).
To convert the ea into 100.00 patients, so that those remainingat any time will be in terms of percentages, divide the formula showing1000.00 by 10. Then the formula will be
yr=100.00(.884593)x5
2. Percentage of patients who have left hospital. - To find thepercentage of patients who have left the hospital, subtract the numberremaining in hospital from the original 100.00.
Patients who haveleft hospital = 100.00 - [100.00(.884593)x5]
Expressed in general terms, the formula is
dx=ea-ea+bx
i. Graduated increase in the number of patients on sick report orin hospital. - Cases of sickness and injury occur from day to day.Patients who are admitted to sick report remain under treatment for, varyingperiods of time, depending chiefly upon the severity of illness or, injury,but to a certain extent upon the proximity of the hospital to the troop
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areas, the facility for returning the men to the organization, etc.Of those admitted to sick report, some will have returned to duty by theend of the first period (5 days in this case), others will go out duringthe second one, while some will remain a longer time, and a few even ayear or more. During the second period, in addition to the cases comingin, a certain number of patients will be remaining from those admittedduring the first one. Also during the third period, in addition to thoseadmitted, cases will be remaining from the first and second ones. And so,the increase in the number of patients will continue as time advances,until all of the first group of cases admitted have left sick report, which,for all practical purposes, will be at the end of one year. After thattime the number, of patients leaving sick report during each period byreturn to duty, deaths, or discharges for disability, will equal the numberadmitted.
j. Integration of basic formula. - To find then the number ofpatients on sick report, or in hospital as the case may be, at any time,add to the number admitted during the period, the number remaining fromall preceding ones. For this purpose the basic formula is integrated betweenthe beginning (M day) and the constantly advancing time, X5.Using the basic formula with one section, the integrated formula is
ydx=(ea+bx/logeb)-(ea/logeb)
Substituting the values already found, and using one seventh of theloge b, the formula for gas patients shows the numberof gas patients in hospital at the end of each 5 day periods
ydx=P=40.774720-[40.774720(.884593)x5]
To find the total patients in hospital on any day, the day's basic admissionsmust be added to the P found from this or any similar formula.
The patients (P) include all who will ultimately return to duty, die,or be discharged as physically disabled. The number who are disposed ofin other ways is so small that it can be omitted from consideration.
k. Formulae for deaths and disability discharges, which have, occurred.-The total number of patients who have left hospital at any time by death,disability, discharge, or duty equals those who have been admitted lessthe number sick in hospital. This is also true of death and disabilitycases when considered separately. The integration of the basic formulashows how many cases, which will ultimately result in death or discharge,are in hospital. Then the difference between that group in hospital andthe total deaths or disabilities expected among the cases which have beenadmitted, constitute the number of fatalities or disability dischargeswhich have already occurred.
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All of the special formulae relating to death or disability cases areexpressed here as parts of the total cases [See Fig. 97, (1) and (2)].Thus, for every patient wounded by gas who is admitted to hospital, .017306will die; and if there are 5 cases admitted there will be 5 times .017306,or .086532, fatalities. The basic formula for the eventually fatal gascases remaining in hospital from 1000.00 of them admitted on any day is(Fig. 97)
yr=863.02(.420133)x7+136.98(.870099)x7
Changing each ebx7 to ebx5;reducing the sum of the two ea, from 1000.00 to 1.00 by dividingeach by 1000.00; multiplying each resulting ea by .017306 toreduce the deaths to parts per total cases; and then integrating
ydx=.239820-[.120563(.538258)x5+.119257(.905389)x5]
This formula shows the gas cases in hospital, who will eventually die.At the end of 30 days the number of such cases is
.239820 - (.002932 + .065689) = .171199
As above, the total patients who have died or who will die out of 5gas cases, is .086532. Consequently, the formula for those who have diedis
.086532x5 - the above formula
At the end of 30 days, or after 6 five day periods, it will be
6 (.086532) - .171199 = .347993
Then at the end of 30 days, if 30 gas cases have been admitted at therate of 1.00 per day, .35 have died, and .17 patients, who are in hospital,will die.
.35 + .17 = .017306 × 30 = .519180
l. Multiple section curves. - When two or three section exponentialcurves are used, the method of developing the formulae from them is thesame as that used for a one section curve; and the only additional stepwhich is required is the summation of the different sections.
S. COMPUTATION OF DATA FOR SHORT DURATION CASES
57. Percentage leaving hospital each day by return to duty or death.- Calculate from the formulae on Figs. 90, 91, and 92 for duty cases; andfrom the last ones on Figs. 96, 97, and 98 for death cases, the percentageof each group who return to duty or die on each day up to and includingthe tenth. These data are shown by Tables 26 and 30, respectively.
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The figures are cumulated and show the percentage of duty or death caseswhich occur during any period from the beginning of the first day the endof the tenth. The percentage leaving hospital on any one day by duty, death,etc., can. be found easily by subtraction.
Table 30. - Percentage ofthe total deaths in hospital which occurred during the first ten days fromthe three classes of cases in the American Expeditionary Forces.
Day after admission to hospital | Diseases and nonbattle injuries* | Gassed? | Gunshot Wounded? |
1 | 7.56 | 10.33 | 17.60 |
2 | 14.59 | 19.48 | 31.61 |
3 | 21.02 | 27.59 | 42.77 |
4 | 26.76 | 34.77 | 51.68 |
5 | 32.16 | 41.15 | 58.81 |
6 | 36.76 | 46.80 | 64.53 |
7 | 41.08 | 51.82 | 69.13 |
8 | 44.86 | 56.28 | 72.84 |
9 | 48.38 | 60.24 | 75.84 |
10 | 51.62 | 63.77 | 78.28 |
* See Fig. 96. ? See Fig. 97. ? See Fig. 98.
58. Average days of treatment. - As an illustration of the method,let us find the average duration of treatment for gassed cases whodie in ten days or less.
a. Divide the percentage of death cases leaving hospital (dying) duringeach day from the first day to the tenth, by the total leaving (dying)during the ten days. The results expressed in parts per 100 show the percentageof those dying in ten days or less who died on each day from the firstto the tenth. (see column 4, Table 31).
b. Beginning with 100; that is, the total percentage to die in 10 days',subtract successively the number leaving, hospital (dying) during eachday from the first to the tenth. The results show the percentage of the10 day fatal cases remaining in hospital each day (see column 5, Table31).
c. Reduce the results to the basis of one case instead of 100% (seecolumn 6, Table 31) and summate. The total shows the eventual death casesin hospital at the end of ten days from the group remaining under treatmentfrom one to ten days, when the daily admission rate of gassed cases whodie during period is 1.00.
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Table 31. - Method of findingthe eventually fatal gassed cases in hospital at the end of ten days amongthose that die in ten days or less, when the daily admission rate fromthe group is 1.00.
Day | Percentage of deaths | Percentage of ten day deaths | Patients remaining§ | ||
Each day | Cumulated* | Leaving hosp.? | Remaining in hosp.? | ||
100.00 | 1.00 | ||||
1 | 10.33 | 10.33 | 16.20 | 83.80 | .84 |
2 | 9.15 | 19.43 | 14.35 | 69.45 | .70 |
3 | 8.11 | 27.59 | 12.72 | 56.73 | .57 |
4 | 7.18 | 34.77 | 11.26 | 45.47 | .45 |
5 | 6.38 | 41.15 | 10.01 | 35.46 | .35 |
6 | 5.65 | 46.80 | 8.86 | 26.60 | .27 |
7 | 5.02 | 51.82 | 7.87 | 18.73 | .19 |
8 | 4.46 | 56.28 | 6.99 | 11.74 | .12 |
9 | 3.96 | 60.24 | 6.21 | 5.53 | .06 |
10 | 3.53 | 63.77 | 5.54 | 0 | 0 |
| Total | 4.55 | ||||
*From Table 30. ?See Par. 58a. ?See Par. 58b §See. Par. 58c.
With an admission rate of 1.00, the eventual death cases under treatment(4.55) is the same as the average days treatment for each one. Table 32shows the average duration of treatment of duty and death cases admittedas sick, gassed, and gunshot wounded, and whose maximal days of treatmentare from one to ten. Thus of the fatal gassed cases which survive fivedays or less, the average days was 2.77; and for the group surviving tendays or less, it was 4.55.
In Table 32, the data for "Duty cases" are computed from thosefor "Duty cases" in Table 26 in same way as Col. 6, Table 32(gassed) are from those in Table 31. The data for "Death cases"in Table 32, are calculated similarly from those in Table 30.
Table 32. - Average durationof treatment of cases in hospital who will return to duty or die, at anytime between one day or less, and ten days or less.
Day | Duty* | Expected to die? | ||||
Sick | Gassed | Gunshot wounded | Sick | Gassed | Gunshot wounded | |
1 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
2 | 1.48 | 1.50 | 1.68 | 1.48 | 1.46 | 1.44 |
3 | 1.94 | 2.00 | 2.34 | 1.95 | 1.92 | 1.85 |
4 | 2.40 | 2.50 | 3.00 | 2.38 | 2.35 | 2.22 |
5 | 2.83 | 3.00 | 3.65 | 2.83 | 2.77 | 2.55 |
6 | 3.26 | 3.50 | 4.27 | 3.22 | 3.15 | 2.87 |
7 | 3.67 | 4.00 | 4.90 | 3.63 | 3.53 | 3.13 |
8 | 4.07 | 4.50 | 5.54 | 3.97 | 3.88 | 3.38 |
9 | 4.47 | 5.00 | 6.15 | 4.35 | 4.22 | 3.61 |
10 | 4.84 | 5.50 | 6.77 | 4.70 | 4.55 | 3.82 |
*From Table 26 ?From Table 30
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59. Patients in hospital on the maximal day. - As stated above,among gassed cases who eventually die and for whom the duration. of treatmentis from one to ten days, there are 4.55 cases in hospital on the tenthday, when the daily admission rate from such cases is 1.00 per day.
a. In the first place, however, only 63.77% of the fatal gassed casesdie within ten days. Consequently to convert the data into terms of totalgassed cases which are fatal, multiply the 4.56 by 63.77%. The resultsshow that when the daily admission rate for fatal gassed cases ofall durations is 1.00, that among, the cases surviving from one to tendays, there are 2.90 (4.55 × 63.77%) such patients in hospital onthe tenth day.
b. In the second place, only 1.73% of all gassed cases treatedin hospital are fatal. Consequently to translate the data to the basisof 1.00 gas admissions per day, the 2.90 must be multiplied by 1.73%. Theresult shows that there are .05 (2.90 × 1.73%) gassed casesin hospital on the tenth day in a group of such cases that will die withinten days, when the daily admission rate from war gases is 1.00 (see Table27).
The data for. the cases who are treated five days or less, six daysor less, etc., are found by the same method.
60. Patients in hospital on any day, when the maximal one is thetenth, etc. - The problem here is to find how many cases there willbe in hospital on any one day, such as the fifth or sixth, in a group ofcases whose treatment is for a longer period; for example, ten days orless. To illustrate the method let us again use the data for the gassedcases who eventually die. The process is the same as in Table 31 untilthe data in the last column are obtained. Then to find the patients inhospital on any day among those surviving ten days or less, proceed asshown by Fig. 22. The following table shows the method in detail.
Table 33. - Fatal gassedcases in hospital on any day in a group surviving ten days or less.
Day | Ten days fatal cases* | Total fatal cases? | Total gassed cases? |
1 | 1.00 | 0.64 | 0.01 |
2 | 1.84 | 1.17 | .02 |
3 | 2.54 | 1.62 | .03 |
4 | 3.11 | 1.98 | .03 |
5 | 3.56 | 2.27 | .04 |
6 | 3.91 | 2.49 | .04 |
7 | 4.18 | 2.67 | .05 |
8 | 4.37 | 2.79 | .05 |
9 | 4.49 | 2.86 | .05 |
10 | 4.55 | 2.90 | .05 |
* Summation from above downward of data, lastcolumn, Table 31,
? Preceding column multiplied by 63.77%.
? Preceding column multiplied by 1.73%.
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Fig. 77. -Histogram and fitted skew curve for daily admission rates from diseasesand nonbattle injuries to hospital and quarters per 1000 strength in 30large camps in the United States during 1918, excluding September and October.
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Fig. 78. -Histogram and fitted skew curve for daily admission rates from diseasesand nonbattle injuries to hospital and quarters per 1000 strength in 30large camps in the United States during 1918, excluding September and October.
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Fig. 79. -Duration of treatment (leaving sick report) of diseases and nonbattle injurycases among white enlisted men in hospital and quarters in the United Statesin 1925 - 1927. 1 2
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Fig. 80. -Duration of treatment (remaining on sick report) of disease and nonbattleinjury cases in hospital and quarters as they occur in the United States
NOTE: Observed points from data as graduated by Fig. 79.
(1) By multiplying (2) by 1.8954.1 2
(2) From integration of formula for curve.
(3) 15.07 (14.0742 + 1.00) was the average number of days lost per casein the U.S. in 1918.2 Multiply (2) by 92.63% to reduce it to(3)
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Fig. 81. -Duration of treatment (leaving hospital) of disease and nonbattle injurycases in hospital as they occur in the United States.
NOTE: Observed points based upon the same data as is Fig. 79, after eliminating91.07% of them as quarter cases as determined by Sect. 1 of Fig. 79.1
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Fig. 82. -Duration of treatment (remaining in hospital) of disease and nonbattleinjury cases in hospital as they occur in the United States.
NOTE: Observed points from data as graduated by Fig. 81.
(1) From integration of formula for curve.
(2) 20.36 (19.36 + 1.00) was the estimated average number of days lostper hospital case in the U.S. in 1918 (Fig. 3, p. 7).
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Fig. 83. -Duration of treatment (leaving hospital) of disease and nonbattle injurycases which occurred in the American Expeditionary Forces in 1918 whilein the A.E.F. and later in the U.S.
NOTE: Observed points from experience with A.E.F. cases during thelast six months of 1918.1
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Fig. 84. -Duration of treatment (remaining in hospital) in the American ExpeditionaryForces and later in the U.S. of disease and nonbattle injury cases whichoccurred in the A.E.F. in 1918.
NOTE: Observed points from data as graduated by Fig. 83.
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Fig. 85. -Duration of treatment (leaving hospital) in the A.E.F. only of diseaseand nonbattle injury cases which occurred there in 1918.
NOTE: Observed points from experience with the A.E.F.cases during the lastsix months of 1918, using only duty cases, deaths, and 40% of the casessent to the U.S. to cover the estimated time lost in the A.E.F. only.1
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Fig. 86. -Duration of treatment (remaining in hospital) in the A.E.F. only of diseaseand nonbattle injury cases which occurred there in 1918.1
NOTE: Observed points from data as graduated by Fig. 85.
(1) From integration of formula of curve.
(2) It is estimated that the average days lost per case in the A.E.F. onlywas 23.75 (22.75 + 1.00). Multiply (1) by 96.575% to reduce it to (2).
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Fig. 87. -Duration of treatment of GAS cases which occurred in the A.E.F. in1918.1
NOTE: The observed points include practically only the time lostby cases while in the A.E.F. The lower curve (b) is sloped so as to includeonly that much time; while the upper one (a) cover all the time lost includingthat after transfer from the A.E.F. The upper curve is obviously a poorfit of the observed points, but it is as good a one as is practicable withthe available data.
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Fig. 88. -Duration of treatment of GUNSHOT cases which occurred in the A.E.F.in 1918.1
NOTE: See Note on Fig. 87.
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Fig. 89. -Duration of treatment of disease and non-battle injury cases who were admittedto hospital in the United States in 1918 and returned to duty.
NOTE: Observed points based upon experience with U.S. cases 1925 -1927,modified to conform to 1918 experience.1 2
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Fig. 90. -Duration of treatment of disease and nonbattle injury cases which returnedto duty while in the A.E.F. in 1918.
NOTE: Observed points based upon experience with duty cases in theA.E.F. during the last six months of 1918.1
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Fig. 91. -Duration of treatment of GAS cases which returned to duty while in theA.E.F. in 1918.
NOTE: Observed points based upon experience with duty cases in theA.E.F. during the last six months of 1918.1
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Fig. 92. -Duration of treatment of GUNSHOT cases which returned to duty while inthe A.E.F. in 1918.
NOTE: Observed points based upon experience with duty cases in theA.E.F. during the last six months of 1918.1
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Fig. 93. -Duration of treatment of disease and nonbattle injury patients admittedto hospital in the United States in 1918, who ultimately died.
NOTE: Observed points based upon experience with U.S. cases in 1918 whichdied.1
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Fig. 94. -Duration of treatment of disease and nonbattle injury patients admittedto hospital in the United States in 1918, who were ultimately dischargedfor disability.
NOTE: Observed points based upon experience with U.S. cases in 1918 whichwere discharged as physically disabled.1
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Fig. 95. -Duration of treatment of disease and nonbattle injury patients admittedto hospital in the United States in 1918, who ultimately died or were dischargedfor disability.
NOTE: Observed points based upon experience with U.S. cases in 1918 whodied (using only one tenth of deaths from influenza and pneumonia) or weredischarged as physically disabled.1
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Fig. 96. -Duration of treatment of disease and nonbattle injury patients admittedto hospital in the A.E.F. in 1918, who ultimately died.
NOTE: Observed points based upon experience with A.E.F. disease and nonbattleinjury cases during the last six months of 1918, who died.1
164
Fig. 97. -Duration of treatment of gas patients admitted to hospital in the A.E.F.in 1918, who ultimately died.
NOTE: Observed points based upon experience with the patients wounded bypoisonous gases in the A.E.F. in 1918, who died.1
165
Fig. 98. -Duration of treatment of GUNSHOT patients admitted to hospital in the A.E.F.in 1918, who ultimately died.
NOTE: Observed points based upon experience with the patients wounded bygunshot missiles in the A.E.F. in 1918, who died.1
166
Fig. 99. -Relationship of the number wounded by poisonous gases to those woundedby gunshot missiles.3
NOTE: The same infantry regiment battle days were used as perFig. 100. As shown by the graph the number of men wounded by war gasesincreased at a slower rate than those wounded by gunshot missiles, actuallycausing a gradual decrease in the number of gas cases per one gunshot caseas the latter increases in number. Thus the number wounded by poisonousgases to each one wounded by gunshot missiles was 1.14 when there were3 of the latter, but only .18 to each one when there was 153.
167
Fig. 100.- Relationship of the number killed by all causes to those wounded by gunshotmissiles or by poisonous gases in 6,022 battle days for infantry regimentsfrom Jan. 1 - Nov. 11, 1918.3
NOTE: The infantry regiments used were those of the following Divisions:-1st, 2nd, 3rd, rth, 26th, 27th, 35th, 42nd, 78th, 79th, and 80th.
The graduated and ungraduated data for those killed in relation to thenumber wounded by gunshot missiles were reduced to 68.52% of the totalkilled, and to those wounded by poisonous gases to 31.48%, which was thesame percentage that gunshot and gas wounds were of the total.
The relative number killed decreased 43% as the number wounded by poisonousgases increased from 10 to 100 per infantry regiment battle day; whileon the other hand the relative number of those wounded by gunshot missilesremained practically constantas the latter increased from 10 to 100.
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