I guessed the next bit.

"And it wasn't insulin in the bottle, but I eserine?"

"Exactly."

"And who gave him the injection?" I asked.

"His wife."

I understood now what Sophia had meant by the "right person."

I asked: "Does the family get on well with the second Mrs. Leonides?"

"No. I gather they are hardly on speaking terms." m t^ It all seemed clearer and clearer. Nevertheless 5 Inspector Taverner was clearly not happy about it. | "What don't you like about it?" I asked him.

"If she did it, Mr. Charles, it would have been so easy for her to substitute a bona ride bottle of insulin afterwards. In fact, if she is guilty, I can't imagine why on earth she didn't do just that."

"Yes, it does seem indicated. Plenty of insulin about?"

"Oh yes, full bottles and empty ones.

And if she'd done that, ten to one the doctor wouldn't have spotted it. Very little | is known of the post mortem appearances in human poisoning by eserine. But as it was he checked up on the insulin (in case it was the wrong strength or something like that) and so, of course, he soon spotted that it wasn't insulin."

"So it seems," I said thoughtfully, "that Mrs. Leonides was either very stupid - or possibly very clever."

"You mean -"

"That she may be gambling on your coming to the conclusion that nobody could have been as stupid as she appears to have been. What are the alternatives? Any other - suspects?"

The Old Man said quietly:

"Practically anyone in the house could have done it. There was always a good store of insulin - at least a fortnight's supply.

One of the phials could have been tampered with, and replaced in the knowledge that it would be used in due course."

"And anybody, more or less, had access to them?"

"They weren't locked away. They were kept on a special shelf in the medicine cupboard in the bathroom of his part of the house. Everybody in the house came and went freely."