feature of interest which I had previously pointed out in the Lowell case of amnesia. It is indicated that the acquired memories in certain forms of amnesia were the first to disappear, while the deeper and more closely knit associations were preserved.

The neurological examination may be briefly summarized as follows: Marked arterio-sclerosis with a high blood pressure, speech occasionally dysarthric, no hemianopsia, grip of right hand decidedly weaker than that of left, no paralysis, pupils slightly unequal, the right reacting slightly to light, the left rigid, the right knee jerk diminished as compared to the left, no Babinski reflex, no facial paresis or deviation of the tongue. The gait was weak but not hemiplegic while the station was normal. There were no sensory disturbances in any of the extremities. All objects were quickly and correctly recognized and named and their uses accurately described. The amnesic aphasia was episodic and usually appeared only after the fatigue of a long examination or in the late afternoon. The patient was clearly oriented and showed no signs of intellectual defect.

An examination of the motility of the left hand showed that while it was slightly weaker than the right, it was free from paralysis, ataxia or tremor. All voluntary movements were present, yet it was possible to demonstrate a typical left-sided motor apraxia. The false motor reactions of the left hand were due to a motor apraxia and not to any inability to understand requests, because there was no intellectual defect and no word deafness. The facial muscles were free from apraxia. The inability to name objects, although he could indicate their uses with the right hand, took place only during the temporary anmesic aphasia due to fatigue. Repetition of printed letters was normal. Copying was correctly done with each hand. All objects were correctly recognized in each visual field and therefore there was no unilateral mindblindness. Astreognosis was absent. The apraxia may be tabulated as follows:

The attempt to show the use of a cork-screw with the left hand is an example of a curtailed reaction, while the persist

ence of saluting movements to different requests indicates a clonic perseveration.

A number of other objects were correctly used in the left hand but in a fumbling and awkward manner. The imitation of movements was also somewhat apraxic on the left. The imitations of movements of the right arm with the left arm led to some interesting reactions. When the patient was requested to make certain movements with the left arm alone, an apraxia always resulted, but this apraxia practically disappeared if the patient was allowed to imitate the movements of the right arm with his left. The apraxia to imaginary movements or in the use of objects was increased when the eyes were closed; or if apraxia was absent when the eyes were open, it tended to appear when the same tests were made with the eyes closed. These observations, demonstrated as in the previous case, that visual impressions are able to partially correct a motor apraxia in the same manner that a subject is less ataxic when the eyes are open.

For an anatomical localizing diagnosis we would suggest a probable area of softening at the angle of the third left frontal convolution and the Sylvian Fissure, extending below to the white matter of the corona radiata and to the radiations of the genu of the corpus callosum (forceps anterior). A lesion here would cause a motor aphasia and also a motor apraxia of the left arm, because the guiding influence of the right side of the brain upon the left side of the body would be cut off. The motor centre would thus become isolated. Here again we see the importance of the integrity of the callosal fibres from preventing any motility disturbance. The weakness and numbness of the right arm is probably due to either a backward extension of the lesion or to a pathological irradiation involving the anterior central convolution on the left.

Any analysis of these two cases demonstrated that the chief difficulty lay in an inability to transfer a subjective choice process into an objective reaction. The cause of this disorder could be easily traced to a definitely localized lesion in the brain, which disturbed the kinetic memories for move

ments and produced new and abnormal combinations. The disordered movements and misuse of objects could be partially corrected through visual impressions, probably because these impressions may have stimulated certain non-affected portions of the brain, to function in a normal manner.

NOTE ON SOME OF THE PHYSICAL FACTORS AFFECTING REACTION TIME, TOGETHER WITH A DESCRIPTION OF A NEW REACTION KEY

By FRANK Angell

The history of reaction-time investigations discloses a curious combination of painstaking accuracy in regard to the functioning of the time-measuring apparatus together with a more or less happy-go-lucky arrangement at the other end of the experiment.

Thus the chronoscope and its standardizing instruments have been the subjects of minute and laborious investigation, whilst the reagent, after assuming his 'convenient and comfortable position' has usually been left to his own devices in carrying out the reaction prescriptions. Whether however the reagent obeyed the directions, whether, for example, wrist and forearm movements did not enter into play where finger movements were prescribed, are matters which the experimenter has rarely been in a position to determine. Indeed it has only been of comparatively recent date that investigation has been directed to the initial pressure, the "antagonistic motion" of the break reaction.

Among other neglected factors in these experiments has been the effect of the tension of the reaction key spring. This has usually been set at a 'comfortable and convenient' resistance, and variations within these 'comfortable and convenient' limits have been regarded as negligible. This may be the case, but it is a minor question quite as well worth investigating as a variation of 2 or 3 sigma in the readings of the chronoscope.

The question was taken up as a "minor study" by two students in the advanced course in psychology- Miss Lanktree and Miss Morrison. The lever arm of a Morse key was set at tensions of 10, 20, 50, 100, and 200 grams respectively, and for each tension 10 series of 10 reactions each were taken. The first of these series does not enter into the averages given in Table I as the fall-hammer showed irregularities in the chronoscope at the time this series was taken. Each day the 5 series were run through twice the second time reversing the order of the first, the order of the several series changing from day to day. The 15 volt current was furnished by a mercury rectifier and maintained at the same strength for

each day, usually at 0.47 amp. The mean variation of the hammer readings ran from one to three sigma-not very accurate but sufficiently so for the purposes of the experiment.' The stimulus came from a sound-hammer placed behind the reagent, who occupied a room adjacent to that of the experimenter. The reagents noted the condition of attention as good, moderate or strained (the last referring to the accompanying muscular tension) and in addition marked the reaction as sensory or muscular. Almost all of the reactions were characterized as sensory; seemingly from strain sensations in the ear adapting it to the direction of the stimulus. L. had already been reagent in another investigation for more than a semester and both had been experimenting on reaction time in the second year's course of laboratory work.

Table I gives the results of the experimentation for the several tensions of the reaction key. It shows noticeable differences for all tensions in case of L. and a noticeable difference between the tension of 200 grams and the remainder of the series for M.

TABLE I

Reaction times for different tensions of spring of telegraph key.
Reagents L. and M.

The introspections do not indicate any marked change in the attitude of the reagents for the stronger pressures of the key. Once M. notes a strain in the hand with 200 grams, but the reaction itself is noted as sensory, i. e., the sensory content of consciousness at the moment of reaction was strain sensations in the head or ears directed toward the source of sound. The increase in tension, therefore, would not seem to result for the reagent in a direction of attention to the hand and a change to the muscular form of reaction. L. asserted that there

It is, perhaps, worth while to note that the chronoscope "neuerer Construction" used in this investigation, with only 4 years of use is a much less steady instrument than our old chronoscope; also "neuerer Construction" which has weathered 20 years of general laboratory service.