| Abstract | Books and card indexes have shortcomings inherent in their unit, which is the page. When we use them as fact-holders they impose on us rigidity in the arrangement of data. A physical aid to thinking, which may be called the group fact manipulator or associator, is described. The apparatus allows the free manipulation at will of prefabricated groups of data for the solution of classificatory problems in medicine and other subjects. If the symptoms of a particular patient are put into the device, it will indicate at a glance the range of differential diagnostic possibilities. It is a supplementary aid and in no way a substitute for books, knowledge, experience, or clinical judgment. Like any tool it can be misused; but time may give it a useful, though limited, place in teaching and practice. |