208 



KNOWLEDGE. 



June, 1913. 



side only of the brain — in the case of the right- 

 handed on the left side — excludes the accuracy of 

 the theory of habit as an explanation of right- 

 handedness. 



Dr. Lueddeckens opposes the widespread belief 

 that left-handedness is a phenomenon restricted to 

 the hand. On the contrary, it affects the physio- 

 logical character of the whole left side, which 

 presents the same characteristics in the left-handed 

 as does the right side in the right-handed. ' This 

 thesis, which Lueddeckens endeavours to confirm in 

 detail, is the leading feature of his researches, 

 together with the preponderance of the left hemi- 

 sphere of the brain over the right as the chief 

 explanation of right-handedness, in which, as we 

 have seen, Bolk and Biervliet also agree. In support 

 of this theory he examines not only the hand but 

 the arm, brain and spine, the ear, speech, walk, 

 sleep, psychic processes, the whole muscular system, 

 and so on, giving particular attention, however, to 

 the eye. His manifold observations have enabled 

 him to recognise left-handedness, as a rule, in the 

 dilation of the left pupil. As science, the statements 

 about the eye are the most important and valuable 

 in his book. 



He emphasises that James Mark Baldwin also 

 considered "the prevalence of the left half of the 

 brain" the natural cause of the predominance of 

 right-handedness, and he quotes from this celebrated 

 investigator's book on the mental development of the 

 child interesting experiments that Baldwin made 

 with his own infant daughter. In the first place he 

 would not allow the child always to be carried on one 

 arm. From the fourth to the tenth month he placed 

 her daily at a fixed hour in a comfortable sitting 

 posture and let her reach out after the most varied 

 objects. During this time he found that no 

 preference was shown for either hand, but it must 

 be noted that no exertion was exacted. As soon 

 as the distance was increased from ten or twelve 

 inches to fifteen inches the child at once evinced 

 a marked preference for the right hand. In the 

 first period of the experiment she stretched out her 

 right hand five hundred and seventy-seven times, 

 her left five hundred and seventy-eight times, and 

 both hands at once one thousand and forty-two 

 times, and in the second period, at an increased 

 distance of the object, out of eighty tests she used 

 her right seventy-four times, the left only five times 

 and both hands together but once. At a distance of 

 thirteen to fifteen inches she used her right hand 

 alone for seizing. If the object were shifted to 

 the left all the greater exertion was made by the 

 right hand in the domain of the left, while there 

 was a diminution in the use of the left hand. On 

 the other hand, I must mention Dr. Manfred 

 FrankePs assertion that Baldwin's experiment, put 

 by himself (Dr. Frankel) " to a test with several 

 children and many trials, in no way verified itself." 



The right-handed only sleep well on the right side 

 as a rule, and if they fall into a heavy sleep on the 

 left side they often have unpleasant dreams, and 



sometimes nightmare or pollution. The left-handed, 

 again, generally only sleep well on the left side. The 

 reason is that the pressure of blood is higher on the 

 right side of the brain with the latter, and on the 

 left side with the former. Similarly also, according 

 to Lueddeckens, the characteristics of the left side of 

 the left-handed correspond in every detail with the 

 characteristics of the right side of the right-handed. 

 As the result of numerous observations, " I was 

 astounded," he writes, " at the degree of conformity 

 manifested by the two states or conditions, resembling 

 an object and its mirrored reflection." He lays 

 great weight on heredity in cases of left-handedness. 

 He gives dates and tables showing the frequent 

 recurrence of left-handedness in one and the same 

 family in many instances. With regard to left- 

 handedness in school children, he says in part : — 

 " Cases of left-handedness are, as a rule, soon 

 noticed at school, especially in writing. Although 

 the scholars, often with great difficulty, learn to 

 write with the right hand the characters that are 

 adapted to right-handedness, very many of them 

 show the inclination to use the left. Later, when 

 they notice that it is unpleasant to write against the 

 point of the nib, they often begin to write from right 

 to left in so-called mirror writing, in which they 

 often attain remarkable facility with a relatively 

 small amount of practice. . . . When requested 

 to write her name with her left hand, a left-handed, 

 mentally deficient schoolgirl of twelve executed it 

 in mirror writing, and when a church with a tower 

 to the left and a house to the right was drawn for 

 her, she copied it with her left hand, beginning at 

 the right side of the paper and drawing the tower 

 first, and then, working towards the left, the house. 

 She had learnt at school to write and also knit in 

 the customary right-handed manner, but at times 

 she fell back to knitting with the left hand. Such 

 cases of mirror knitting are probably rare in 

 Germany, though another case had been noticed 

 before in the same school. In any case, it proves 

 what technical difficulties will be overcome instinct- 

 ively, even where there is mental deficiency, by left- 

 handedness in order to assert itself." 



According to Wilhelm Fliess also, in " Vom Leben 

 und vom Tod," in no case are the two sides of the 

 body in perfect symmetry, the left side being more 

 developed in one person and the right in another. 

 Other investigators as well are of the same opinion, 

 but there is novelty in Fliess' assertion that " the 

 significance of both sides changes with these 

 deviations, so that manly women and womanly 

 men manifest a fuller development of the left side 

 of their bodies. Left-handed men are always more 

 womanly, and left-handed women more manly, than 

 the right-handed of their sex. . . . When there 

 is deviation in the characteristics of the sexes and 

 the man is more effeminate, his female side, the left, 

 has a fuller development; and when the woman is 

 more masculine her male side, also the left, is more 

 developed." The connection between the accentua- 

 tion of the " left " side principle and the mixed 



