The Author studies the relations between the physical and psychical resemblances in two groups of similar (18 pairs) and dissimilar (21 pairs) twins.
The physical characters considered are: the measurements and indexes of the head, face and nose.
The psychical characters are: attention, auditive memory, visual memory, taste for colours and mental level.
The similar twins betray great resemblance with regard to the measurements and indexes of the head and face and very notable differences with those of the dissimilar twins (excepting the measurements and indexes of the nose).
With regard to the psychical characters studied, many (visual memory, taste for colours, mental level, concordance in mistakes) do not show any notable differences. The auditive memory (weak) and the index of attention (very high) betray, however, notable differences. No correlation is observed between physical resemblance (given in millimetres) and concordance in mistakes; while the relation is strong between physical resemblance and the index of attention.