DEXTRAL PRE-EMINENCE. 



847 



quantitative examination was made, the proportion of cholesterine was 6*245 

 parts per 1,000 (Flint). The meconium contains cholesterine and no ster- 

 corine, the stercorine, in the adult, 

 resulting from a transformation of 

 cholesterine, by the digestive fluids, 

 which probably are not secreted dur- 

 ing in trail terine life. 



None of the secretions concerned 

 in digestion appear to be produced 

 in utero, and it is also probable that 

 the true, biliary salts are not formed 

 at that time; but the processes of 

 disassimilation and excretion are 

 then active, and the cholesterine of 

 the meconium is the product of the 

 excretory action of the liver. The 

 relations of cholesterine as an ex- 



, . . . . , , , FIG. 316. Cholesterine extracted from meconium. 



crementitious product have already 



been very fully discussed, in connection with the bile and with excre- 

 tion. 



Dextral Pre-eminence. Most persons by preference use the right arm, 

 leg, eye etc., instead of the left ; but exceptionally some use the left in pref- 

 erence to the right. There can be no doubt with regard to the fact of a 

 natural, dextral pre-eminence ; and also, that left-handedness is congenital, 

 difficult if not impossible to correct entirely, and not due simply to habit. 

 It would appear that there must be some condition of organization, which 

 produces dextral pre-eminence in the great majority of persons, and left- 

 handedness, as an exception ; but what this condition is, it is very difficult 

 to determine. An explanation which was offered by anatomists is that the 

 right subclavian artery arises nearer the heart than the left, that the right 

 arm is therefore better supplied with arterial blood, develop's more fully, and 

 therefore is generally used in preference to the left ; but the exceptional pre- 

 dominance of the left hand can not be explained in this way. 



The most important anatomical and pathological facts bearing upon the 

 question under consideration are the following : Boyd has shown that the 

 left side of the brain almost invariably exceeds the right in weight, by about 

 one-eighth of an ounce (3'5 grammes). In aphasia the lesion is almost al- 

 ways on the left side of the brain. These facts point to a predominance of 

 the left side of the brain, which presides over the movements of the right 

 side of the body. Again, a few cases of aphasia with left hemiplegia, the 

 lesion being on the right side of the brain, have been reported as occurring 

 in left-handed persons. Ogle gives several such instances, in which the 

 brain-lesion was on the right side. In two left-handed individuals, the brain 

 was examined and compared with the brain of right-handed persons. It was 

 found that the brain was more complex on the left side in the right-handed, 

 and on the right side, in the left-handed. Bastian has found the gray matter 



