It may readily be seen that such definiteness and uniformity as this classification possesses results from the introduction of more or less arbitrary criteria for the differentiation of the various types of reactions. The question might arise, To what extent do the distinctions thus made correspond to reality? To consider, for instance, our rule for the placing of sound reactions (50 per cent of the sounds of the shorter word to be present, in the same order, in the other word): when a given reaction (_man--minstrel_) is in accordance with the rule assigned under the heading of sound reactions, can it be assumed that sound similarity and not some other relationship is the determining factor of the association in question? Or when in, a given instance (_cabbage--cobweb_) the sound similarity falls somewhat short of the standard required by the rule, can it be assumed that sound similarity is not, after all, the determining factor? Similar questions may, of course, arise in connection with other subdivisions. It must, indeed, be conceded that objective methods can reveal but indirectly and with uncertainty the inner mechanism which produces any association and that in any given instance it would be impossible to establish the correctness of grouping in accordance with such methods. However, to decide that question for any given reaction is really not necessary in practice, since an error made through wrongly placing one, two, or three reactions tinder any heading is of no significance; the types acquire importance only when represented by large numbers in a record under consideration; and when many reactions fall tinder a single heading the likelihood of error, as affecting the record as a whole, is by that fact alone greatly reduced. The whole question might more profitably be approached from another point of view: To what extent are the distinctions of this classification useful? An answer to this question can be found only in the results. § 7. ANALYSIS OF PATHOLOGICAL MATERIAL We present in Table IV, the results of a statistical examination of the records obtained from certain groups of normal subjects and from some groups of insane subjects. The normal groups have been studied for the purpose of determining the frequency and manner of occurrence among normal subjects of the various of abnormal reactions. It seemed best for this purpose to consider separately the records of those subjects who gave an unusually large number of individual reactions. Fifty-three records containing fifteen or more individual reactions were found after a fairly diligent search among our normal test records. In the other groups of subjects--persons of common school education, persons of collegiate education, and children--we included no records containing more than ten individual reactions. The more striking departures from average normal figures are indicated in the table by the use of heavy type.