I was not unprepared for this request, for I had noticed how his pets went on increasing in size and vivacity, but I did not care that his pretty family of tame sparrows should be wiped out in the same manner as the flies and spiders. So I said I would see about it, and asked him if he would not rather have a cat than a kitten.

His eagerness betrayed him as he answered, "Oh, yes, I would like a cat! I only asked for a kitten lest you should refuse me a cat. No one would refuse me a kitten, would they?"

I shook my head, and said that at present I feared it would not be possible, but that I would see about it. His face fell, and I could see a warning of danger in it, for there was a sudden fierce, sidelong look which meant killing. The man is an undeveloped homicidal maniac. I shall test him with his present craving and see how it will work out, then I shall know more.

10 pm. I have visited him again and found him sitting in a corner brooding. When I came in he threw himself on his knees before me and implored me to let him have a cat, that his salvation depended upon it.

Vocabulary:

Vivacity: Here it means 'life and energy'
Betray: Give away a secret
Lest: As a precaution. In case.
His face fell: He suddenly looked sad
A homicidal maniac: An insane killer
Craving: A need to have something
Brooding: Thinking and getting upset
Implore: Beg