PROCEDURE. Say: "_What is the difference between a fly and a butterfly?_" If the child does not seem to understand, say: "_You know flies, do you not? You have seen flies? And you know the butterflies! Now, tell me the difference between a fly and a butterfly._" Proceed in the same way with _stone and egg_, and _wood and glass_. A little coaxing is sometimes necessary to secure a response, but supplementary questions and suggestions of every kind are to be avoided. For example, it would not be permissible for the examiner to say: "_Which is larger, a fly or a butterfly?_" This would give the child his cue and he would immediately answer, "A butterfly." The child must be left to find a difference by himself. Sometimes a difference is given, but without any indication as to its direction, as, for example, "One is bigger than the other" (for fly and butterfly). It is then permissible to ask: "_Which is bigger?_" SCORING. Passed if a real difference is given in _two out of three comparisons_. It is not necessary, however, that an _essential_ difference be given; the difference may be trivial, only it must be a real one. The following are samples of satisfactory and unsatisfactory responses:-- _Fly and butterfly_ _Satisfactory._ "Butterfly is larger." "Butterfly has bigger wings." "Fly is black and a butterfly is not." "Butterfly is yellow (or white, etc.) and fly is black." "Fly bites you and butterfly don't." "Butterfly has powder on its wings, fly does not." "Fly flies straighter." "Butterfly is outdoors and a fly is in the house." "Flies are more dangerous to our health." "Flies haven't anything to sip honey with." "Butterfly doesn't live as long as a fly." "Butterfly comes from a caterpillar." Sometimes a double contrast is meant, but not fully expressed; as, "A fly is small and a butterfly is pretty." Here the thought is probably correct, only the language is awkward. Of 102 correct responses, 70 were in terms of size, or size plus color or form; 12 were in terms of both form and color; 6 in terms of color alone; and the rest scattered among such responses as those mentioned above. _Unsatisfactory._ These are mostly misstatements of facts; as: "Fly is bigger." "Fly has legs and butterfly hasn't." "Butterfly has no feet and fly has." "Butterfly makes butter." "Fly is a fly and a butterfly is not." Failures due to misstatement of fact are of endless variety. If an indefinite response is given, like "The fly is different," or "They don't look alike," we ask, "_How is it different?_" or, "_Why don't they look alike?_" It is satisfactory if the child then gives a correct answer. _Stone and egg_