She thus found that the worm was sensitive to cold, coming to the surface when the temperature was high, and disappearing to deeper parts when she was exposed to cold. As soon as she had recovered strength so far as to be able to go out of doors the visits of the worm to the eye became fewer, perhaps a week or longer occurring between them. It usually put in an appearance when she was near a cosy fire or in bed. Its last disappearance was for two months, during July and August, and as she at that time passed a worm _per rectum_ she thought she had thus got rid of it. During these two months she was mostly in the open air, but as soon as, in September, the rooms began to be heated, it again came to the surface. When I first saw Miss H—, in June, I very thoroughly examined the eye, but failed to observe any trace of the parasite, unless perhaps the appearance of a minute bluish vesicle at the extreme outer angle of the conjunctival cul-de-sac corresponded to one of the extremities of the worm, but the vesicle, though watched for a time, did not alter in position or appearance. I gave her strict injunctions to return at any time whenever she felt the worm on the move. I saw her twice at the eye wards of the Royal Infirmary about the beginning of July, but on these occasions careful inspection was again negative in its results. On the 12th of September, however, she again came to the Infirmary, stating that she had felt the worm moving about in the left eye that forenoon, and to prevent it leaving the surface she had kept the eye well covered with a warm cloth till she made her way to the Infirmary. On this occasion, after examining the eye for a minute or two, I observed the worm moving in a tortuous, wriggling manner under the conjunctiva, the surface of which became slightly elevated as it moved along. It passed with a pretty quick movement over the surface of the sclerotic at the distance of about 5 mm. from the outer margin of the cornea. It glided from the upper outer towards the lower outer part of the globe. There was increased lachrymation and slightly increased injection of the conjunctiva,—just such an appearance as would result from a particle of dust in the eye. I at once placed my finger on the surface of the globe in such a manner as to prevent the parasite passing backwards until the conjunctiva was pretty well anæsthetised by the application of cocaine. I then got my friend Dr. Maddox, who was present, to apply his finger while the necessary preparations were hastily made for an operation.