Chapter I.General Considerations—Normal Standards of External Brain Architecture—New Details of Unusual Forms of Convolutions and Furrows—Many Deviations from Type accepted from Several Observers—Chief Deviations from Usual Form in Brains examined by the Writer, and the lines on which they occur; their significance and appraisement from a general point of view.In an Address' in the Section of Psychology at the Annual Meeting of the British Medical Association, London, 1895, I touched upon some of the results of an analysis of many necropsies I had made, with regard to abnormal forms and arrangements of brain convolutions, and mentioned the dissatisfaction one had felt with some of the accepted standards of convolutional form. With regard to unsatisfactory standards of normal brain-form, it was stated in the Address that “we may take it for granted, and need not tarry to prove, that a different normal standard of brain-form obtains in different stages of individual life, in different races of mankind, and, as a logical inference, must obtain also in different ages of the world and epochs of time; for what practically concerns us at the moment is the normal set of standards for modern British brains. The standards of the normal, hitherto chiefly in use, and with which I began, were unsatisfactory, defective, incomplete, insufficient in range, and even misleading. For their unsatisfactoriness there are several reasons. One is that some of them have been diagrammatic or schematic, thus unduly accentuating some features and minimising or omitting others. Another is that the brains from which certain figures and descriptions are drawn have been taken from dissecting-room subjects, or from patients—most of them ‘incapables’ of various kinds, dying in rate-supported or State-supported institutions—of whose life-history little or nothing is known in many instances; who often are failures in life—waifs and strays—broken fragments of the wreckage of civilisation, the indication of degeneracy and breakdown. and such failures, waifs and wreckage are they very often—most often, indeed—because of their mental defect or perverted aberrant type of mind, which not infrequently has as its accompaniment, sometimes pathological brain change; but sometimes also, or solely, has an abnormal brain development and aberrant gyral conformation. Indeed, knew we their ancestral and life-history fully, we would search such subjects for some of the most interesting forms of convolutional deviation from type. and still more would this be the case, if, especially in the past and in some countries, dissecting-room subjects have been largely recruited from the criminals dying in prisons, and the mentally decayed and defective dying in asylums. Therefore it is not surprising to find that sometimes the brains taken from the sources previously referred to, and published as typical, are what I do not hesitate to declare and describe as being brains of deranged or of defective development, and utterly misleading if taken as normal.”
The Races of Mankind: being a Popular Description of the Characteristics, Manners, and Customs of the Principal Varieties of the Human Family