To me it seems probable that what Samuel Butler insists upon is true, and that the origin of variations must be looked for in the needs and experiences of the creature varying. But let this pass, as it opens up too large and difficult a question to enter upon here. The effects of environment and function must act as a kind of arbiter directing conduct and, in particular, mental expression. It is the very A B C of the question that appropriate training and opportunities of use are essential if any mind is to develop. Supply such mental stimuli to the boy and man, deny them to the girl and woman, and then call "the art impulse of the nature of a male secondary sexual character," because woman has as yet played but a small and secondary part in any of the arts! The source of error is so plain that one can only wonder at the fallacies that have been accepted as truth. Thus, when one finds so just and careful an investigator as Havelock Ellis saying, "It is unthinkable that a woman should have discovered the Copernician system!" it can but be regarded as an example of that sex-bias which marks so strikingly men's statements on this subject of mental sex-differences. We may well ask, Why unthinkable? As answer I will give the finely just acknowledgment of Iwan Bloch on this very question. He refers to this statement of Havelock Ellis, and then says, "I need merely call to mind the widely known physical discoveries of Madame Curie, whose thoroughly independent work qualified her to succeed her husband as professor at the Sorbonne. We cannot, therefore, exclude the possibility that in the sphere of the natural sciences notable discoveries and inventions may be made in the future in consequence of the independent work of women."[322] To take another instance. We find the fact that so far women have gained very small distinction in music, contrasted with the great number of girls who are trained to play on musical instruments. But this is surely to show a complete misunderstanding of the question. It is like saying that the best preparation for a painter to know the colours reflected on water by a cloudy or sunny sky would be a course of optics. Music is at once the most imaginative and the most severely abstract of the arts, and the absence of women from music must be referred to deeper causes, which yet, it seems to me, are not far to seek.