la describing the relative sizes of unequal pupils in the diseases of the central organ of the nervous system (as in incomplete general paralysis) most observers make special mention of the dilated pupil, and, under precisely similar essential conditions, we more frequently find one pupil characterised as being larger than the other, than the converse. Were there no prejudice at the bottom of this custom, there might be nothing to advance against it; but I believe that the views on which it is founded, are, more or less, conjectural. It is apparently assumed, in the first place, that inequality of the pupils is always caused by lesion of one iris only; that dilatation of the pupil is more truly and more frequently a morbid condition, than contraction; and, finally, that dilatation is always dependent on relaxation, resulting from paralysis. The iris, with the dilatated pupil is, thus, more often pointed out as being affected, and that with paralysis, than the one in which the pupil is contracted; and we find, moreover, that it is quite usual to adduce, not perhaps, mere inequality, but dilatation of the pupils generally, as an absolute sign and example of paralysis of single muscles.