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adopted and in use throughout the army during the past few months differ radically from those originally recommended. They may be described summarily as follows:

There are four principal systems or stages in the examination. First comes the procedure of segregation, by means of which the original group, which may, if examining rooms permit, include as many as five hundred men, is split into two subgroups; (a) the literates, men who can speak and read English fairly well, and (b) the illiterates, men who are relatively unfamiliar with the English language. These two groups must necessarily be treated somewhat differently, therefore the literates are given a group examination known as Alpha, which consists of eight markedly different tests. This examina tion, although it requires almost no writing on the part of the subject, does demand facility in using written and oral instructions. The illiterate group is given an examination known as Beta, which is in effect Alpha translated into pictorial form. In this examination pantomime and demonstration supplant written and oral instructions.

Each group examination requires approximately fifty minutes. Subjects who fail in Alpha are ordinarily given opportunity to improve their ratings by taking Beta, and subjects who fail in Beta are given individual examination in order that they may be more accurately and justly rated than in the group examination alone.

Any particular individual may have to take one, two or three of these types of examination, thus for example, a man of low grade literacy who happens to get into examination Alpha may also have to take Beta and some form of individual examination.

Examination papers for both Alpha and Beta are scored rapidly by the use of

stencils and the resulting rating is promptly reported to the appropriate military authority.

By means of this system of examinations it is possible for an examining staff consisting of four psychologists and a force of scoring clerks to examine as many as one thousand men per day.

Every man examined by one or more of the procedures described is assigned a numerical rating and in addition a letter grade which indicate his general intellectual ability or mental alertness. The numerical rating is used only for statistical purposes, the letter grade for practical military purposes. The latter alone is reported ordinarily to military officers and recorded on the soldier's service record and qualification card.

The letter grades which are in use are defined as follows: A designates very superior intelligence; B, superior intelligence; C, high average intelligence; C, average intelligence; C-, low average intelligence; D, inferior intelligence; D, very inferior intelligence. The letter E has been reserved for the designation of men whose mental ability is seemingly inadequate for regular military duty.

Commissioned officers usually possess and obviously should possess A or B intelligence. Many excellent non-commissioned officers possess C or C+ intelligence, but in the main this group is composed of men with C+ or B ratings. The great body of privates grades C. Men with D or D— intelligence are usually slow to learn and rarely gain promotion. Many of them, especially the D- individuals, can not be used to advantage in a military emergency which demands rapidity of training. The results of army mental testing indicate that the majority of D- and E soldiers are below ten years mental age. A few fall as low as three or four years.

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The contrast between A and D telligence becomes impressive when it is shown that men of A intelligence have the requisite mental ability to achieve superior records in college or professional school, whereas Dindividuals are rarely able to pass beyond the third or fourth grade of an elementary school, however long they may attend.

Reliability of Methods.-The methods of mental examining used in the army have been found to possess reliability as well as practical value which far exceeded the expectations of the men who are responsible for them. Indeed, the success of this particular methodological undertaking is a remarkable demonstration of the "fecundity of aggregation." It is extremely unlikely that any individual working alone would have developed within reasonable time equally valuable methods of group examining. Inasmuch as reliability is of first importance, various measures of the validity of the army mental tests are presented.

The probable error of an Alpha score is about five points. This is approximately one-eighth of the standard deviation of the scores for unselected soldiers. The reliability coefficient of examination Alpha approximates .95. This group examination correlates with other measures of mental ability as follows: (1) With officers' ratings of their men, .50 to .70 for the total Alpha score and .30 to .54 for the separate tests; (2) with Stanford-Binet measures of intelligence, .80 to .90 for the total Alpha score and .31 to .85 for the separate tests; (3) with the Trabue B and C Completion tests combined, .72 for the total score and .39 to .76 for the separate tests; (4) with Examination Beta, .80; (5) with the composite result of Alpha, Beta and StanfordBinet examinations, .94; (6) in the case of school children results of Alpha examina

tion correlate (a) with teachers' ratings .67 to .82, (b) with school marks .50 to .60, (c) with school grade location of thirteen and fourteen year old children .75 to .91, (d) with age of children .83 (for soldiers the correlation of Alpha score with age is practically zero).

The Alpha examination given with double the usual time allowance correlates approximately .97 with the regular time examination.

The following data indicate the reliability of Examination Beta: It correlates with Alpha, .80; with Stanford-Binet, .73; with the composite of Alpha, Beta and Stanford-Binet, .915. The correlation of the separate Beta tests with the StanfordBinet ranges from .47 to .63 (average .58). Results of Beta given with double time allowance correlate with those obtained with the regular time allowance .95.

For the several forms of individual examination used in the army the principal correlations at present available are as follows:

Results obtained by repetition of Stanford-Binet examination of school children correlate .94 to .97. Results of one half of the scale compared with the other half correlate .94 to .96. An abbreviated form of the Stanford-Binet examination consisting of two tests per year was used extensively in the army. The results of this abbreviated scale correlate .92 with those obtained by use of the complete scale.

For the Point Scale examination the measures of reliability are practically the same as for the Stanford-Binet.

A Performance Scale examination prepared especially for military use consisted of ten tests. Results for the several tests of the scale correlate with Stanford-Binet results, .48 to .78. Five of the ten tests yield a total score which correlates .84 with the Stanford-Binet score. The same

five tests correlate .97 with the results of the entire scale.

Summary of Results.—After preliminary trial in four cantonments psychological examining was extended by the War Department to the entire army, excepting only field and general officers. To supply the requisite personnel, a school for training in military psychology was established in the Medical Officers' Training Camp, Fort Oglethorpe, Georgia. Approximately one hundred officers and more than three hundred enlisted men received training at this school.

The work of mental examining was organized finally in thirty-five army training camps. A grand total of 1,726,000 men had been given psychological examination prior to January 1, 1919. Of this number, about 41,000 were commissioned officers. More than 83,000 of the enlisted men included in the total had been given individual examination in addition to the group examination for literates, for illiterates, or both.

Between April 27 and November 30, 1918, 7,749 (0.5 per cent.) men were reported for discharge by psychological examiners because of mental inferiority. The recommendations for assignment to labor battalions because of low grade intelligence, number 9,871 (0.6+ per cent.). For assignment to development battalions, in order that they might be more carefully observed and given preliminary training to discover, if possible, ways of using them in the army, 9,432 (0.6+ per cent.) men were recommended.

During this same interval there were reported 4,744 men with mental age below seven years; 7,762, between seven and eight years; 14,566, between eight and nine years; 18,581, between nine and ten years. This gives a total of 45,653 men

under ten years mental age. It is extremely improbable that many of these individuals were worth what it cost the government to maintain, equip and train them for military service.

The psychological rating of a man was reported promptly to the personnel adjutant and to the company commander. In addition, all low grade cases and men exhibiting peculiarities of behavior were reported also to the medical officer. The mental rating was thus made available for use in connection with rejection or discharge, the assignment of men to organizations and their selection for special tasks. The mental ratings were used in various ways by commanding officers to increase the efficiency of training and to strengthen organizations by improved placement.

It was repeatedly stated and emphasized by psychological examiners that a man's value to the service should not be judged by his intelligence alone, but that instead temperamental characteristics, reliability, ability to lead and to "carry on" under varied conditions should be taken into account. Even after the feasibility of securing a fairly reliable measure of every soldier's intelligence or mental alertness had been demonstrated, it remained uncertain whether these measurements would correlate positively with military value to a sufficient degree to render them useful. Data which have become available during by indicating a relatively high correlation the past year settle this question definitely between officers' judgments of military value and the intelligence rating.

The various figures which follow are presented not as a summary of the results of psychological examining in the army but instead as samples of these results, the chief value of which is to indicate their principal relationship and practical values. (To be concluded.)

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It is estimated that the total radium production in the United States to 1919 approximates 55 grams of radium element, and this represents, probably, more than half of all the radium produced in the world.

There has been some discussion lately by members of the Bureau of Mines as to the amount of radium that can be produced from the carnotite fields, as well as suggestions that mesothorium, a by-product from monazite, should replace radium in the luminous material which has found extensive use in the war on airplane and ship instrument dials, compasses, and many indicating devices, and which will find extensive use on watches and clocks, etc.

The estimates of Dr. Moore, of the Bureau

of Mines, are based on a very inadequate

study of the carnotite region made prior to the war and before the fields had been developed to any great extent. The carnotite holdings of the Standard Chemical Company, which are the largest under the control of a single company or individual and comprising about 350 claims, have been carefully studied -in part by systematic diamond drilling-and this work has been the basis for an estimate that at the least 500 grams of radium should be produced from carnotite. This is five times greater than Dr. Moore's estimate.

As regards mesothorium as a radium sub

stitute, there are several points whose importance Dr. Moore and the Bureau of Mines have overlooked or minimized, in their anxiety to conserve radium. Statistics show that before the war considerably less than one thousand tons of monazite was worked up in the United States per annum in the production of thorium nitrate, and it is estimated that about three thousand tons of monazite supply the world's needs for thorium nitrate. Each ton of monazite containing about 5 per cent. of thoria (corresponding to good Brazilian concentrates) will yield about two milligrams of commercial mesothorium, so that per annum there may be expected a world's mesothorium production of about six grams. The cost of producing monazite will always prevent the production of mesothorium except as a by-product. Unlike radium, which has a half-decay period of 1,700 years and can be used in luminous material immediately after refining and for medical purposes after thirty days' aging, mesothorium has a comparatively brief half-decay period of 5.5 years and its economical use in luminous compound is only possible a year or two after refining. For medical purposes, the short life and varying gamma ray activity of mesothorium make this product less desirable than radium. The following table given by McCoy and Cartledge1 shows the change in gamma-ray activity of pure mesothorium in time, due to the gradual decay of mesothorium I. (the parent product) and the increase and decrease of radiothorium, which produces thorium D with its very penetrating gamma rays.

THE CHANGE OF GAMMA RAY ACTIVITY OF MESOTHORIUM WITH TIME

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The figures given under Th D are based upon the amount of radiothorium which accumulates in mesothorium, and it is this product which also measures the alpha-ray activity of mesothorium. It is evident from the figures given under Th D that the alpha-ray activity of pure mesothorium reaches a maximum between the fourth and fifth year after its preparation and, further, that it is less than 50 per cent. "aged" one year after preparation. In spite of the fact that commercial mesothorium owes a proportion-probably 20 per cent.-of its activity to the presence of radium, it follows that it would be uneconomical to use mesothorium in luminous compound until it had aged for a year or two. It seems evident that the small supply available, the varying activity and the necessity for prolonged aging of mesothorium are some of the reasons that make this material less desirable than radium, both for medical purposes and in luminous compound, especially with an assured supply of radium wholly adequate for both requirements.

PITTSBURGH, PA.

CHARLES H. VIOL

STATISTICAL STUDY OF THE
INFLUENZA EPIDEMIC

THE American Public Health Association, Vital Statistics Section, appointed a Committee on Statistical Study of the Influenza Epidemic on November 20, 1918. Under the auspices of this committee, a meeting of the state and municipal registrars in the eastern states was held at the University of Pennsylvania, Hygiene Laboratory, Philadelphia, Pa., on November 29 and 30, 1918. There were present, also, at this initial conference, several private statisticians interested in the public health statistics of the epidemic and the results to be derived from study of such data. A series of suggestions was made up, mimeographed and sent to statistical and public health workers for criticism. At the meeting of the Vital Statistics Section in Chicago on December 11, the committee submitted a report on its activities and asked for authority to continue further inquiry into a program of statistical study of

the epidemic. The section authorized the continuance of the committee and provided that representatives of the United States Bureau of the Census, of the United States Army and Navy, of the United States Public Health Service, of the state and municipal health boards, and the various statistical, sociological, actuarial and economic associations be represented thereon. The committee was specifically authorized to act in an advisory capacity first, to outline the various sources of data, the minimum standards of tabular and registration practises to be observed by the several organizations providing data, and second, to bring in recommendations on the pathometric or mathematical analysis of published epidemic data. The committee was divided into four subcommittees as follows:

Subcommittee A: Registration and Tabulation Practise of the Federal Departments. (Wm. H. Davis, M.D., chief statistician, Division of Vital Statistics, Bureau of the Census, Chairman; Richard C. Lappin, Recorder.)

Subcommittee B: Registration and Tabulation Practise of the State Departments and Commissions. (Otto R. Eichel, M.D., director, Division of Vital Statistics, New York State Department of Health, Albany, Chairman; Edwin W. Kopf, Recorder.)

Subcommittee C: Registration and Tabulation Practise of Municipal Boards of Health and of Private Public Health Agencies. Chas. Scott Miller, M.D., Philadelphia Department of Health, Philadelphia, Pa., Chairman.)

Subcommittee D: Pathometry (mathematical analysis and interpretation) of the Epidemic. (Charles C. Grove, Ph.D., Columbia University, Chairman; Arne Fisher, F.S.S., Recorder.)

Mr. E. W. Kopf was delegated to act as chairman of the General Committee and to coordinate the work of the several subcommittees. The General Committee of the Vital Statistics Section was authorized to cooperate in statistical matters with the Influenza Reference Committee of the entire association.1

1 See "Influenza Bulletin.'' American Public Health Association, Boston, December 13, 1918.

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