‘Will you kindly place yourself with your back to the window?’ he said. ‘I am going to apply what is called the catoptric test. You have probably heard of it?’
‘My ignorance of scientific matters is fathomless.’
The other smiled, and at once offered a simple explanation of the term. By the appearance of the candle as it reflected itself in the patient’s eye it was possible, he said, to decide whether cataract had taken hold upon the organ.
For a minute or two he conducted his experiment carefully, and Yule was at no loss to read the result upon his face.
‘How long have you suspected that something was wrong?’ the surgeon asked, as he put down the candle.
‘For several months.’
‘You haven’t consulted anyone?’
‘No one. I have kept putting it off. Just tell me what you have discovered.’
‘The back of the right lens is affected beyond a doubt.’
‘That means, I take it, that before very long I shall be practically blind?’