CASE 50.--Mr. K--, æt. 29, suffered from paresis of the right abducens in the autumn of 1877. In December, 1878, convergent squint is present, linear deviation 5 mm. (scarcely more on the left than on the right). The defect of movement towards the side of the right abducens amounts to about 2 or 3 mm. Diplopia is present in the whole visual field with increase of the deviation towards the right. Emmetropia and full visual acuteness on both sides. Tenotomy of the internal rectus and advancement of the abducens of the right eye at the end of December. Three weeks later single vision is present in the middle line; on the left limit of the visual field crossed double images, on the right side homonymous ones, beginning about 20° from the middle line. The result was by no means excessive. In convergent squint with congenital paresis of the abducens, not much can be attained without shortening the abducens. Of course only the squint can be removed, not the paralysis, but if once a correct position is attained for the middle line, cosmetic demands are satisfied; the outward movement, which is absent, must be replaced by turning the head. The chief method for absolute divergent squint is the combination of shortening with tenotomy of the externus. If the impulse for convergence is once lost, so that an associated movement occurs in place of an accommodative one on fixation of a point situated on the middle line, a removal of the squint cannot be obtained by simple tenotomy of the externi--another proof that a change of position of the eye is by no means a necessary result of tenotomy.