On the average for the 3 days, November 4, 18, and December 16, the men of Squad B have average eye movement time which, in the case of movements left, ranges from 88.0 to 117.5 σ, Sne and Fis. The average for all is 96.3 σ, the average variability 8.3 per cent. In the case of movements right the range is from 81.7 to 104.5 σ for How and Fis, respectively. The average for the 10 subjects usually discussed is 89.3 σ, the variability 8.6 per cent. Thus the members of Squad B show no values which are on the one hand as small, or on the other as large, as the limiting ranges of the group of 1917.

Table 181. - Squad B - Eye Movement Speed And Its Variability

[L. and R. designate left and right movements, M. and S. D. in σ, and C. in per cent].

Squad B had two dates with the eye movement measurements, January 14 and 20, under conditions of reduced diet. These results are averaged at the bottom of table 181. The average for L is 98.8 σ, which can be compared with the 96.3 σ of the normal. The average for R is 90.9 σ as against 89.3 σ. The indications are, therefore, that the eye movements were slightly slower during the period of the reduced diet.

Table 180 shows the data of eye-movement speed for Squad A. At their first session, October 28, 3 weeks after the beginning of the reduced diet, the average speed for left movement was 96.6 σ and variability 7.3 per cent. The average speed for right movement was 93.1 σ with variability 6.6 per cent. Individual subjects ranged, left, from 84 to 112 σ for Gul and Gar, and for right from 76 to 114 σ for Kon and Spe.1 In the variability for left movements, the men ranged from 3.3 to 10.4 for Vea and Tom. For right movements they ranged from 4.7 to 11.0, Can and Gul and Mon.

The individuals of Squad A have averages for the dates October 28, November 25, December 9, January 13, and January 27.2 The averages for all of these dates are shown at the bottom of table 180. The total average for the 10 men is for left movements, 101.6 σ, for right, 93.3 σ. The variability is 9.1 and 8.3 per cent, respectively, for left and right. Thus all of the averages for eye movements shown by members of Squad A fall within the range found for the normal series of 1917.

The influence of the low-diet condition upon this muscle coordination process may be judged better from the data presented in diagrammatic form in figures 117 and 118. In figure 117 the solid lines represent, as in other curves, the data of Squad A. The two curves in each case are designated L and R, for left and right. The speed of the movements left shows a definite and regular lengthening with the progress of the experiment. The time requirement gradually increased from about 97 to 106 σ, a lengthening of 9.3 per cent. It is true that not all of the subjects of Squad A demonstrate this same change. For example, Can has values for the left movements for the different dates as follows: 94, 88, 94, 87, and 87 σ. On the other hand, we may point out Gar, whose values for left are 112, 114, 108, 120 and 131 σ. With the majority of subjects the length of time tends to increase from October 28 until January 27. The eye movements to the right (see solid line for R in fig. 117) show almost no progressive change during the low-diet period. This difference between the right movements and the left movements is a surprising fact, but it absolutely agrees with results previously found in this Laboratory.1 It was found in the investigation with small amounts of alcohol that with the eye movements the alcohol effect was predominantly upon movements to the left in the ratio of 10 to 4.

Fig. 117. - Speed of the eye movements.

L and R designate movements to the left and to the right. Solid lines represent Squad A, broken lines Squad B.

1The record of 114 σ for Spe is associated with an error in the procedure in that the left eye was not covered. 2The measurement was also used on November 11, but owing to a difficulty with the apparatus the records were nearly all failures.

Squad B (see the broken line in fig. 117) demonstrates a wide range of variation between their three normals, November 4, November 18, and December 16. Some uncontrolled influence was operating on November 18, but definite information is lacking. It is very apparent that it influenced the movements to the left more strongly than it did those to the right. The average results for the low-diet dates January 14 and 20 show slower speed than the two normal dates, November 4 and December 16. This is particularly true with the movements to the left, thus agreeing with the results for Squad A. Including in the average the aberrant values of November 18 with these normals for November 4 and December 16, it is still true, as shown in table 181, that the average for the low diet shows slower speed than for normal conditions. The results of the two squads therefore substantiate each other in the direction of the low-diet effect on this neuro-muscular process of eye movements. It appears with both groups of men that the muscle coordination of moving the right eye from a point at the right of the field of vision to a point at the left is more delicate and easily disturbed than the complementary coordination for movements of the same eye from a point at the left through 40° to the right.

Fig. 118. - Variability in the speed of the eye movements.

L and R designate movements to the left and to the right. Solid lines represent Squad A, broken lines Squad B.

1Dodge and Benedict, Carnegie Inst. Wash. Pub. No. 232, 1915, p. 163, table 26.

The average variability of the two squads for right and left movement is presented in figure 118. Squad A appears to show a gradual increase in the variability, which is high for December 9, January 13, and January 27, except that on the latter date the variability for R was decreased. In the case of Squad B the variability is larger on November 18 than for the other two normal dates. It also rises at the point of January 20 during the low-diet experiment. Squad B shows no considerable increase in the variability at their first low-diet date. This would appear to agree, also, with Squad A. Since the first date for Squad A, October 28, was during the early part of the low-diet period and showed a variability of nearly 7 per cent, we judge this to be about as small as could reasonably be expected.

Associated with the prolonged reduced diet the eye movements show a slower speed in the case of Squad A amounting in the extreme to approximately 5 per cent for averages of movements right and left. With this there is also an increase in the variability. The results for this measurement found on Squad B confirm the direction of those observed with Squad A.