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Show 302 MR. H. M. WALLIS ON THE GROWTH [Mar. 2, see them projecting in this direction on all parts of the ear which adjoin the line of insertion [to the head.-H. M. W.~] and upon the outside answering to the convexity of the concha ; but away from there, if you set aside the upper part of this internal [sic] surface, where the hairs come from the front [sic] to the back, w e see on the remaining [portion] the hairs turn obliquely little by little from a downward direction to the outside, so that in the turn inwards [sici] to the posterior tract of the free margin, they become pointed upwards, as w e have seen already. " From what we have said it will be easily understood that the free margin of the outer ear is traversed by two currents of hairs-one which follows the upper tract (or first third) bending downwards; the other which follows the hinder tract, or remaining two-thirds of its free margin, bending upwards. " A t the junction of the upper tract with the lower the two currents meet, and together with hairs coming straight from the hinder surface, sometimes form a true little tuft (ciufetto), the spiral twist upon its convexity being plainly to be observed. " Well, now, Avhat seems worthy of note is, that when Darwin's Tubercle is present, this meeting of the two currents of hairs is placed in correspondence with it. And since in the ears of animals that have hairy ears it is towards the point that the hairs are turned, it seems definitely resolved that Darwin's Tubercle is, as Darwin put it, the rudiment or trace of originally pointed ears." ii. Ears of Infants. Leaving now the historical resume, I proceed to describe some observations which prove that the hairs upon an infant's ear are arranged upon a definite plan and have different directions in different parts of the organ. To begin with, the back of the ear at birth is frequently clothed with a regular growth of hair. The possible significance of this will be dealt with later. For the moment, however, I merely draw attention to the peculiarities of the growth, its constant adherence to certain lines-both on the back of the concha, where the hairs are directed backwards and downwards (as may be seen by reference to Plate X I X . figs. 2 and 3); and upon the back of the helix and anti-helix, where the lines of growth followed by the hair, though in m y experience constant (when hair is present at all), are apparently capricious, a question to be dealt with presently. Fig. 3 shows the back of an infant's ear enlarged. The tract immediately around Darwin's Point, or where Darwin's Point is to be expected (for it is not always present), is bare. Those parts of tbe helix which are above the bare tract are clothed back and front with hairs directed towards Darwin's Point, whilst the hairs upon the back of the antl-hellx separate themselves from those upon the back of the concha, which are directed downwards tow ards the lobe, and executing a countermarch, as one niigbt say, come |
