Tyler's chair legs crashed solidly to the floor.

"I see," he said. "You think this thing has some connection with your own experiences. How long ago was that?"

"Slightly over two months."

"You think the same man...?"

"I don't know. But who could want, as a newspaper story I just read says, to steal the brains of men? What for? It sounds like Barter.

I've never heard of anybody else with such an obsession. I'm putting two and two together--and fervently hoping they'll add up to seven instead of four. For if ever in my life I wanted to be wrong it's now."

Tyler pursed his lips. Bentley saw that his eyes were glinting with excitement.

"But there's a possibility you're right. Do you know what the Mind Master's first manifesto said? It was published by a tabloid newspaper as a sort of gag--a strange crank letter. Here it is."

Tyler tossed Bentley a newspaper clipping a week old. Bentley read quickly:

"The white race is deteriorating physically at a dangerous rate. In fifty years, if nothing is done to prevent it, the world will be filled with men whose bodies are so soft as to be almost worthless. But I shall take steps to prevent that, as soon as I am ready. I need a week. Then I shall begin my crusade to make the white race a race of supermen, whom I alone shall rule. They shall keep the brains they have, which shall be transferred to bodies which I shall furnish.

(Signed) The Mind Master."

Tyler squinted at Bentley again.

"You see? Brains are all right, he says, but the white race needs new bodies. If he isn't suggesting brain subst.i.tution, what is he suggesting? Though I confess I never thought of your story until your name was sent in to me a while ago. For the world thinks of Barter as having been killed by the great apes."

"Yes, I told newspaper reporters that. I thought it was true. But this Mind Master must be Barter. There couldn't be two persons in the world with mental quirks so much alike."

"Tell me what Barter looks like. Oh, there are plenty of pictures extant of the famous Professor Caleb Barter who disappeared from the world some years ago, but he'll know that, of course, and he won't look like the pictures.

"Alteration of his own features should be easy for a man who juggles brains."

"He may have changed his features since I saw him, too," said Bentley.

"But I'm sure I'd know him."

Tyler's telephone rang stridently.

He took down the receiver. His mouth fell slackly open as his eyes lifted to Bentley's face. But he recovered himself and slapped his hand over the transmitter.

"Anybody know you came here?" asked Tyler.

Bentley shook his head.

"Well," went on Tyler, "I don't know how it happens, but this telephone message is for you!"

Bentley's heart seemed to jump into his throat. One of those hunches which sometimes were so valuable to him had struck him, as though it were a blow between the eyes. His lips tightened. His face was pale, but there was a grim light in his eyes.

He hesitated for a second, the receiver in his hand, his mouth against the transmitter.

"Well, Professor Barter?" he said conversationally.

There came a gasp from Thomas Tyler. He jumped to the door and motioned to someone. A man in uniform came to his side. Bentley distinctly heard Tyler tell the man to have this telephone call traced.

From the receiver came a well-remembered chuckle.

"So you were expecting me, eh, Bentley? You never really believed that one of my genius would fall such easy prey to the great apes did you?"

"Of course not, Professor," said Bentley soothingly. "It would be an insult to your vivid mentality."

"_Vivid_ mentality! _Vivid_ mentality! Why, Bentley, there isn't another brain in the world to compare with mine. And you of all people should know it. The whole world will know it before I'm finished, for I have made tremendous strides since you helped me to perform that crowning achievement in Africa. By the way, tell your friend Tyler, who just called the officer to the door, that it's useless to try to trace this call!"

Bentley jumped as though he had been stung. How had Barter known what Tyler was doing? How had he guessed what Tyler had told the man in uniform? How had Barter known Bentley was visiting Tyler? How had he discovered even that Bentley was back in the United States? Why, besides, was he so friendly with Bentley now?

"You speak, Professor," said Bentley softly, "as though you could see right into police headquarters."

"I can, Bentley! I can!" said Barter impatiently, as though he were rebuking a schoolboy for saying the obvious.

"You're close by, then?"

"No. I'm a long way--several miles--from you. But I can see everything you do. And you needn't look at Tyler in such surprise!"

Bentley started. He had looked at Tyler in a surprised way and, clever though he was, he didn't think that Barter could have _guessed_ so accurately to the second the gesture he had made. Barter chuckled.

"It's a good jest, isn't it? But listen to me, Bentley, I've a great scheme in hand for the amelioration of mankind. I need your help, mostly because you were such an excellent subject in my greatest successful experiment."

"Will it be the same sort of experiment as the other?" Bentley's heart was in his mouth as he asked the question.

"Yes, the same ... but there are improvements I have succeeded in perfecting since the creation of Manape. My one mistake when Manape was created was in that I allowed myself to lose control of him--of you! That will not happen again. Oh, if you'll help me, Bentley, that operation will not be performed on you until you yourself request it because I shall have proved to you that it is better for you. You shall be my a.s.sistant and obey my orders, nothing more."

Lee Bentley drew a deep breath.

"If I prefer not to work with you again, Professor?"

A chuckle was Barter's answer. The chuckle broke off shortly.

"You should not refuse, Bentley," said the scientist at last. "For then I should find it necessary to remove you. You might stand in my way, and though you would be but a puny obstacle, you still would be an obstacle. For example, consider Ellen Estabrook, your fiancee. I can find no use for her ... and she knows as much about me as you do.

Therefore, at my convenience, I shall remove her."

"Caleb Barter," Bentley's voice was hoa.r.s.e with anger as he dropped his soothing mode of address toward the man he knew was insane, "if anything happens to Miss Estabrook through you I shall find you no matter how well you are guarded ... and I shall destroy you bit by bit, as a small boy destroys a fly. For every least evil thing that happens to Miss Estabrook, a hundred times that will happen to you at my hands."

"Good!" snapped Barter, no longer chuckling. "I am happy to know how much she means to you. It shows me how easily I may control you through her. It means war then, between us? I'm sorry, Bentley, for I like you. In a way, you know, you are my creation. But in a war between us, Bentley, you haven't a chance to win."