Differences between the sexes have been established also by means of experimental psychology, based upon the examination of a very large number of instances. Berthold Hartmann has studied the childish circle of thought, by means of a series of experiments. Schoolboys to the number of 660 and schoolgirls to the number of 652, at ages between five and three-fourths and six and three-fourths years, were subjected to examination. It was very remarkable to see how, in respect to certain ideas, such as those of the triangle, cube, and circle, the girls greatly excelled the boys; whereas in respect of animals, minerals, and social ideas, the boys were better informed than the girls. Characteristic of the differences between the sexes, according to Meumann, from whom I take these details and some of those that follow, is the fact that the idea of "marriage" was known to only 70 boys as compared to 227 girls; whilst the idea of "infant baptism" was known to 180 boys as compared to 220 girls. The idea of "pleasure" was also much better understood by girls than by boys. Examination of the memory has also established the existence of differences between the sexes in childhood. In boys the memory for objects appears to be at first the best developed; to this succeeds the memory for words with a visual content; in the case of girls, the reverse of this was observed. In respect of numerous details, however, the authorities conflict. Very striking is the fact, one upon which a very large number of investigators are agreed, that girls have a superior knowledge of colors. There are additional psychological data relating to the differences between the sexes in childhood. I may recall Stern's investigations concerning the psychology of evidence, which showed that girls were much more inaccurate than boys. It has been widely assumed that these psychical differences between the sexes result from education, and are not inborn. Others, however, assume that the psychical characteristics by which the sexes are differentiated result solely from individual differences in education. Stern believes that in the case of one differential character, at least, he can prove that for many centuries there has been no difference between the sexes in the matter of education; this character is the capacity for drawing. Kerschensteiner has studied the development of this gift, and considers that his results have established beyond dispute that girls are greatly inferior in this respect to boys of like age. Stern points out that there can be no question here of cultivation leading to a sexual differentiation of faculty, since there is no attempt at a general and systematic teaching of draughtsmanship to the members of one sex to the exclusion of members of the other.