944 



GENERATION. 



greatest physiological importance, is cholesterine. Although but few crystals of cho- 



lesterine are found upon microscopical examination, the simplest processes for its ex- 

 traction will reveal the presence of this 

 principle in large quantity. In a specimen 

 of ineconium in which we made a quantita- 

 tive examination, the proportion of choles- 

 terine was 6-245 parts per 1,000. It is a 

 significant fact, that the meconium contains 

 cholesterine and no stercorine, the sterco- 

 rine, in the adult, resulting from a trans- 

 formation of cholesterine by the digestive 

 fluids, which are probably not secreted dur- 

 ing intra-uterine life. 



None of the secretions concerned in di- 

 gestion appear to be produced in utero, and 

 it is also probable that the true biliary salts 

 are not formed at that time ; but we know 

 that the processes of disassimilation and 

 excretion are then active, and the choles- 

 terine of the meconium is the product of the 

 excretory action of the liver. The relations 



of cholesterine as an excrementitious principle have already been very fully discussed, in 



connection with the bile and with excretion. 



FIG. 313. Cholesterine extracted from meconium 

 inch objective. 



Dextral Preeminence. The curious fact, that most persons by preference use the 

 right arm, leg, eye, etc., instead of the left, while, as exceptions, some use the left in 

 preference to the right, has excited a great deal of discussion, even among the earlier 

 writers. 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 preeminence in the great majority of 

 persons, and left-handedness, as an exception ; but what this condition is, it is very diffi- 

 cult to determine. An explanation, very often 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, develops more fully, and is, consequently, generally 

 used in preference to the left ; but we cannot explain the exceptional predominance of 

 the left hand by an inversion of this arrangement of vessels. 



The most important anatomical and pathological facts bearing upon the question 

 under consideration are the following: Dr. Boyd has shown that the left side of the brain 

 almost invariably exceeds the right in weight, by about one-eighth of an ounce. In 

 aphasia, the lesion is almost always 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 per- 

 sons. These points we have noted in treating of the nervous system. 



Dr. Ogle, in a recent paper on right-handedness, gives several instances of aphasia in 

 left-handed persons, 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 per- 

 sons. 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. In the discussion which followed the 

 presentation of this paper, Dr. Charlton Bastion stated that he had found the gray mat- 

 ter of the brain to be generally heavier on the left than on the right side. With regard 

 to the cause of the superior development of the left side of the brain, the only explana- 



