The figures in the tables printed above contain the results of this investigation, and answer, in part at least, the questions raised at the beginning. They seem to point to the following general conclusions:

(1) The mental defects among idiots are by no means equaled by the bodily. In fact, in measurements of height and weight the defectives are indistinguishable from ordinary children.

(2) In general, at least as far as intelligence is concerned, idiots do not form a separate species, but simply occupy a position at the

extreme of some large distribution, probably approximately that expressed by the normal probability curve.

(3) Among idiots there is not an equal lack of mental capacity in all directions. There is something of the same lack of correlation among the traits measured in the case of idiots as there is with ordinary people.

As I have already stated, these conclusions are drawn directly from the tables of measurements, but in order to make clear the fact that the figures warrant these conclusions I will take them up one at a time and show the way in which each was reached. The first point is that the mental deficiency of the idiots as compared with ordinary children is in no way equaled by bodily deficiency.

§ 12. Results Bearing on Physical Status

THE following table gives the comparison of defectives with children in general, in terms of the percentage of each in the measurements taken which fall above a given point.

For normal children 50 per cent. will fall above the median and 50 per cent. below in every test; 75 per cent. will fall above - 1 P. E. and 25 per cent. below, and 91 per cent. above

TABLE XXXIII.

DEFECTIVES

Per cent. above
Median for Ordi-

2 P. E.

nary Children

Height (7)
Weight (8)

45

61

44

66

Pulse (9)

49

69

86

It is evident from these figures that in the measurements of heig and weight the defectives almost reach the standard of children

general, there being only 5 per cent. and 6 per cent. less of the defectives at the median point than of school children. In the tests of memory and of intelligence1 only 10 per cent. and 5 per cent.,

per cent. and 0 per cent., respectively, of defectives reach the 50 per cent. grade of the other children. The same thing holds true if we notice in each case the percentage of those above minus once the P. E. and minus twice the P. E. In the physical measurements there are about 4 times as many defectives above - 1 P. E. and about 2.5 times as many above - 2 P. E. as there are in the memory and intelligence tests. Without doubt there is a decided difference between the bodily and mental deficiency.

The same facts are emphasized by the following graphic representations. In every surface the zero point represents the median for school children in general; the figures on the right of the zero point are positive multiples of the P. E. and those on the left are negative multiples. Therefore the children whose grade is indicated on the right of the zero point are above the standard for children at large in that particular measurement and those occurring on the left of that point are below the ordinary ability. The figure at each point shows how much above or below ordinary ability in multiples of one tenth of the P. E.

Figs. 6, 7 and 8, which show the distributions for the physical measurements of height, weight and pulse rate, show clearly that the distributions are almost normal, the curves following pretty closely the usual probability curve, the cases clustering about the zero point, i. e., the median of the distribution of cases in general. On the other hand the curves 14 to 23 inclusive, which show the distributions for memory and intelligence, are anything but normal, being decidedly skewed towards the negative end.

These facts, then, seem to justify the conclusion before mentioned and to show that whatever idiots may be on the mental side, as far as concerns physical conditions of growth, nutriment, etc., they are not far from ordinary children. 'The evidences of constitutional weakness, of slow growth and of inferior size,' which by many are held to be characteristic of mental deficiency, do not appear. These children were certainly not two inches shorter and nine pounds lighter than children in general.

It may be objected that the idiots examined were a selected group and that is the reason for the high results. True, the very worst idiots were not included in these measurements, those poor wretches so deformed that they can neither walk nor stand, but on the other

I use this word rather loosely, as these tests may not be any more of a measurement of 'intelligence' than some of the others used.