es painful. Why? Iritis.

"In any case, a chronic irritation came into your case some time.
Little by little there came a heavy exudation around the edges of the
inflamed iris. It was so heavy that we call it a 'plastic' exudation.
Now, that was what was the technical trouble of your eye--plastic
exudation.

"This exudation, or growth, as we might call it, went on from the edges
of the iris until it met in the middle of the pupil. Then there was
spread across the aperture of your lens an opaque granulated curtain
through which light could not pass. Therefore you could not see. The
plastic exudation had done its evil work as the result of the
iritis--that is to say, of the sufferings of the iris."

"I begin to understand," said Mary Gage. "That covers what seemed to
happen."

"It covers it precisely, for that is precisely what did happen. It was
not cataract. I knew, or thought I knew, that it was not from retinal
scars due to inflammation in the back of the eye. It was just a
filling up of the opening of the eye.

"So I know you lost sight in that last eye little by little, as you did
in the other. You kept on knitting all the time. On your way out you
struck the glare from the white sands of the plains in the dry country.
At once the inflammation finished its exudation--and you were blind."

She sat motionless.

"Sometimes we take off the film of a cataract from the eye; sometimes
even we can take out the crystalline lens and substitute a heavy lens
in glasses to be worn by the patient."

"But in my case you intend to cut out that exudation from the pupil?"

"No. I wish we could. What we do is to cut a little key-hole
aperture, not through the pupil, but at one side the pupil. In other
words, I've got to make an artificial pupil--it will be just a little
at one side of the middle of the eye. You will hardly notice it."

"But that will mean I cannot see!"

"On the contrary, it will mean that you can see. Remember, your eye is
a lens. Suppose you put a piece of black paper over a part of your
lens--paste it there. You will find that you can still make pictures
with that lens, and that they will not be distorted. Not quite so much
illumination will get into the lens, but the picture will be the same.
Therefore you will see, and see finely.

"Now, you must not be uneasy, and you must not think of this merely as
an interesting experiment just because you have not heard of it before.
My old