"I'm a neurologist."

That was good, Rick thought. A neurologist was exactly what Marks seemed to need.

"Do you make anything of this?" Dodd asked.

The doctor shook his head. "Nothing. I've never seen a case like it.

I've never even heard of one. In fact, I know of only one a.n.a.logue, and it's an electronic one. Do you know how computers work? The big electronic brains?"

The three nodded.

"Then you will understand. I have worked with computers, and now and then one of them suddenly starts turning out gibberish for no apparent reason. A check of the circuits may show that everything is functionally normal. Yet, the gibberish continues. Often it clears up, with no more reason than it started. Sometimes this happens when the machine is cold, before it is properly warmed up. At other times, it happens when the machine is tired."

"Tired?" Dodd looked his disbelief. "Machines don't get tired. Not in those terms."

Chavez smiled. "Perhaps not. Yet, to those who work with them, it does sometimes appear that the machine is tired. There is really no other expression for it."

Rick knew something of this through his a.s.sociation with Dr. Parnell Winston of the Spindrift staff. Winston was an expert in the new science of cybernetics, which is defined as the science of communications and control mechanisms in both living beings and machines.

"Parnell Winston would know," Rick said.

"He most certainly would," Chavez agreed. "Are you aware that he and I have worked together? My interest was in the biological portion of the project. His was in the electronic. Of course we worked as a team with other specialists."

"Under whose auspices?" Dodd asked quickly.

"Let us be candid," Chavez invited. "Obviously, this is not an ordinary case. The guarded language Hartson Brant used was indication enough of that. Rick Brant I identify because of his resemblance to my friend, and I think I identify Don Scott, of whom I have heard a great deal from Hartson. But who are you, Mr. Dodd?"

For answer, Tom Dodd took out his identification folder and handed it to the physician.

Chavez studied it. "I know your organization, Mr. Dodd. But what is of greater importance for the moment, your organization knows me. I suspect it was for that reason Hartson Brant selected me for you to consult." He gestured to the phone. "You will want to call your office. My records are in New York."

Dodd's face expressed his relief. "I was a little nervous," he admitted. "It was a choice between possibly risking further damage to Marks or taking a chance on someone based only on a recommendation from Dr. Brant. I'm glad you're in the clear."

He went to the phone and called New York. In a moment he said, "Dodd here. Check on Dr. Constantine Chavez." He held the phone for perhaps half a minute, then said, "Roger. That does it."

He held out his hand to the neurologist. "Glad to know you, Doctor.

Can you take over?"

"Not only can I take over, you would have trouble getting rid of me.

This man is obviously hurt in a way that is strange to me, and I a.s.sure you, my experience with damaged minds is considerable. He may be somewhat under the influence of a drug--I will check more thoroughly--but that is not the cause. If I may make a quick and highly tentative guess, this mind is suffering from some kind of trauma induced from an outside source."

"You mean it's not a disease?" Rick asked quickly.

"Precisely. I know of no disease that would behave like this. I can't even imagine a disease with these symptoms."

"How can you be sure?" Scotty pressed.

"Obviously I can't at this stage of investigation. But you must recognize that a physician develops a rather definite feeling for injury after years of experience. My own experience tells me that mental damage of this scope is almost always accompanied by other symptoms when it is the product of a disease. No, I cannot credit the idea of a pathogenic organism too seriously. It is as though some outside agent pierced the cranium and cut off the control centers of the brain."

"A dagger of the mind," Scotty murmured.

Chavez looked up sharply. "Yes! An ideal phrase for it."

Rick recognized the quotation from his school-work. _Macbeth_, Act II.

Another of Shakespeare's phrases from the same work leaped into his mind. "Macbeth hath murdered sleep." Not Macbeth, but Marks. Rick knew he wouldn't sleep well that night, nor for many nights to come.

Dagger of the mind! Well, it fitted. Watching the blank face of what had been, only hours before, a brilliant scientist, Rick could feel its deadly point himself.

CHAPTER X

Search for Strangers

The good weather turned bad, and dark clouds hung low over the New Jersey coast. It was appropriate weather for the state of mind at Spindrift. With Marks a victim of the mysterious "dagger of the mind,"

only Dr. Morrison remained of the original team.

The question, of course, was "Who next?"

At Hartson Brant's urgent request, Steve Ames visited the island and a meeting of all staff was called in the big library.

Rick and Scotty sat on a library table, while the scientists occupied the few library chairs. Steve Ames sat on Hartson Brant's desk and acted as chairman for the informal session.

By mutual agreement, the girls had been excluded. Jan was nearly in a state of shock over what had happened to Marks. Not only was she fond of the crusty scientist, but she was fearful that the mysterious ailment would strike her father next. And Barby was rapidly catching the same fear. After all, new team members probably were not immune, and Hartson Brant, Julius Weiss, and Parnell Winston were deeply involved in the project.

Steve called the meeting to order. "Hartson, you suggested that I come, which I was glad to do. Suppose you start by telling us what you had in mind."

"Very well, Steve." The scientist's glance embraced his colleagues and the boys.

"We have a problem that must be solved before we can continue with calm and objective minds on the project that faces us. The problem is simply, what is the ailment that has stricken three of us, and what is its cause?"

Hartson Brant tamped tobacco into his pipe thoughtfully. "Let us see what we know. First of all, two team members were stricken in Washington, within a short time of each other. They were examined by competent specialists who arrived at no conclusion. They admitted they were unable to diagnose the ailment. The possibility of an unknown disease was considered briefly, but not seriously. The possibility of a chemical agent--a drug, if you like--also was considered. This possibility has not been entirely rejected. However, a detailed laboratory investigation disclosed no trace of chemicals in the patients, apart from chemicals that were expected, of course."

"Could there be chemicals that left no trace?" Scotty asked.

Hartson Brant shook his head. "No one can claim total knowledge of body chemistry, obviously. Just the same, the elements to be found in the body, and the proportions in which they occur, are well known. I said the possibility has not been entirely eliminated, but it seems unlikely that chemical interference caused the disruption."

"What does that leave?" Steve inquired.

The scientist shrugged. "I can't even guess. Physical interference, perhaps. There is also a possibility, which is very difficult to explore, that the ailment was caused within the minds of the scientists by some catalytic agent, or by some psychic trauma that we can't even imagine."

Rick and Scotty exchanged glances. They had seen the ailment at work, and even its effects were almost beyond description. Its cause was hard to imagine.

"But, to continue. Steve recognized the possibility that the ailment was caused by some outside source. Call it an enemy source, if you prefer. He acted to get the remaining team members beyond reach of the enemy by smuggling them to Spindrift. He succeeded with Dr.

Miller--excuse me, Dr. Morrison. He did not succeed with Dr. Marks.

What does this suggest?"

"That hiding Dr. Morrison was an effective preventative," Steve Ames concluded.