II

“Tommy, will you leave this to me? Just for once, you see, I am the bull that has been more than twenty minutes in the arena.”

Tommy nodded.

“You shall be the Captain of the Ship, Tuppence,” he said gravely. “We’ve got to get to the bottom of this.”

“First of all,” said Tuppence as they entered the house, “I must ask Miss Logan one more question.”

She ran upstairs. Tommy followed her. She rapped sharply on the old lady’s door, and went in.

“Is that you, my dear?” said Miss Logan. “You know you are much too young and pretty to be a detective. Have you found out anything?”

“Yes,” said Tuppence. “I have.”

Miss Logan looked at her questioningly.

“I don’t know about being pretty,” went on Tuppence, “but being young, I happened to work in a hospital during the War. I know something about serum therapeutics. I happen to know that when Ricin is injected in small doses hypodermically immunity is produced, antiricin is formed. That fact paved the way for the foundation of serum therapeutics. You knew that, Miss Logan. You injected Ricin for some time hypodermically into yourself. Then you let yourself be poisoned with the rest. You helped your father in his work, and you knew all about Ricin and how to obtain it and extract it from the seeds. You chose a day when Dennis Radclyffe was out for tea. It wouldn’t do for him to be poisoned at the same time⁠—he might die before Lois Hargreaves. So long as she died first, he inherited her money, and at his death it passes to you, his next of kin. You remember, you told us this morning that his father was your first cousin.”