For several days after the operation the probe will have to be passed, both to prevent the wound in the canaliculus from healing up, which it is too apt to do, and also to gradually dilate the nasal duct if it has been previously strictured. Probes and directors of various sizes are required; in fact very much the same instruments (in miniature) as are required for the treatment of stricture of the urethra. Mr. Greenslade has invented a very ingenious little instrument, of which, through his kindness, I am able to show a woodcut (Fig. X.), for slitting up the canaliculus without having to fit the knife in the groove. [Illustration: FIG. X.] PTERYGIUM, the reddish fleshy triangular growth, with its base at the inner canthus, and its apex spreading to and often over the cornea, requires invariably a small operation for its removal. In most cases it will be found sufficient merely to raise the lax portion over the sclerotic with forceps, and divide it freely, removing a transverse portion. If it has encroached upon the cornea, the portion interfering with vision must be dissected off with great care and removed. In some cases, however, it has been found that after removal of a large pterygium, a retraction of the caruncle and the semilunar fold is apt to take place, which renders the eyeball unpleasantly prominent. To avoid this the pterygium may be carefully dissected up from its apex to near its base, and then displaced laterally either upwards or downwards, its apex and sides being stitched to a previously prepared site of conjunctiva. OPERATION FOR CONVERGENT STRABISMUS.--_Division of the internal rectus._--_Subconjunctival operation._--The spring-wire speculum (C) separating the lids, the surgeon divides the conjunctiva by a pair of scissors in a horizontal line (Fig. XI. A A) from the inner margin of the cornea, a little below its transverse diameter to the caruncle, then snipping through the sub-conjunctival tissue, he passes a blunt hook bent at an obtuse angle under the tendon of the internal rectus, and endeavours by depressing the handle to project the point of the hook at the wound. Then with successive snips of the scissors he divides the tendon on the hook, close to its sclerotic margin. Lest it should not be freely divided, various dips with the hook may be made to catch any stray fibres left untouched; but very great care should be taken not to wound the conjunctiva beyond the first horizontal cut in it. The tendon being divided satisfactorily, the edges of conjunctiva should be replaced, and the eye closed for a few hours. [Illustration: FIG. XI.[85]]