“Only—­show me—­what to do,” she cried.  “I will be the nurse!”

. . . . . . .

Several days later, when we had recovered sufficiently from the diabolical attack that had been made upon us, Kennedy was again at work in the laboratory, while I was writing.  We still felt rather weak, but Godowski’s skill had pulled us out all right.

Our speaking-tube sounded and I knew that it was Elaine and Aunt Josephine.

“How do you feel?” inquired Elaine anxiously, as she almost ran across the laboratory to Craig.

“Fine!” he exaggerated, brightly.

“Really?” she repeated anxiously.

“Look!” he said, turning to his microscope.

He took some blood from a test tube in our electric incubator and placed a drop on a slide.  It was some of the blood infected by the germs carried by the tick.

“That is how our blood looked—­before the new nurse arrived,” he smiled, while Elaine looked at it in horror.

Then he pricked his arm and let a drop smear on another slide.

“Now look at that—­perfectly normal,” he added.

“Oh—­I’m so glad,” she exclaimed radiantly.

“Normal—­thanks to you.  You saved us.  You were just in time,” cried Craig taking both her hands in his.

He was about to kiss her, when she broke away.  “Craig,” she whispered, blushing and looking hastily at us.

Aunt Josephine and I could only smile at the disgusted glance Craig gave us, as he thrust his hands in his pockets and wished us a thousand miles away at that moment.

CHAPTER V

SHADOWS OF WAR

For a long time Kennedy had, I knew, been at work at odd moments in the laboratory secretly.  What it was that he was working on, even I was unable to guess, so closely had he guarded his secret.  But that it was something momentous, I was assured.

Long Sin had already been arrested and it was a day or two after the escape of Wu himself who had come just in time to prevent the confession by one of his emissaries of the whereabouts of his secret den.  Kennedy had Chase and another detective whom he frequently employed on routine matters at work over the clues developed by his use of the sphygmograph.  Elaine, anxious for news, had dropped in on us at the laboratory just as Kennedy was hastily opening his mail.

Craig came to a large letter with an official look, slit open the envelope, and unfolded the letter.  “Hurrah!” he cried, jumping up and thrusting the letter before us.  “Read that.”

Across the top of the paper were embossed in blue the formidable words: 

United States Navy Department, Washington, D. C.

The letter was most interesting: 

Professor Craig Kennedy, The University, New York City.

Dear sir,