"Nobody seems to know very much about it," replied Frank. "It has appeared at various places in Germany, especially in the occupied zones. It seems to have attacked Germans as well as Americans, and nobody knows what to make of it. Of course, remember I'm only telling you what another fellow told me recently, and I give it to you for what it's worth. It may be just rumor, but he seemed to be so certain of his facts that I felt inclined to believe him."
As it happened, what Frank had heard as a rumor was indeed a fact— and a fact, moreover, that was proving most puzzling and unpleasant for the American medical authorities. The disease that Frank had spoken of had indeed made its appearance in various parts of the country, and while the doctors had many theories concerning it, they were all only theories as yet, and nothing really definite was known regarding it. The symptoms were much like those of virulent typhus. Men sickened and died within forty- eight hours, and once stricken, the unfortunate victim did not recover in one case out of a hundred.
Some of the doctors were inclined to think it one of the plagues that usually follow in the track of war, due to privation and depression. This theory, however, did not explain why American troops, well fed and victorious, should be affected. Most believed it to be caused by some deadly germ, hitherto unknown, and every effort was being made by the medical corps to isolate the germ and find a remedy for the disease. But the Army Boys were to know more of the source of this strange scourge and make a most amazing discovery regarding it.
CHAPTER XIV
ON THE TRAIL
On the day following that of Tom Bradford's disappearance, Bart and Billy were assigned to special duty as part of an officers' escort on a mission to a neighboring town.
After they had left Frank found himself very lonely, especially as he had an afternoon off duty. Mingled with his thoughts of the missing Tom was the thought that had constantly haunted his mind of late—the unsolved mystery of the alley up which hostile Germans could flit and apparently disappear into thin air. He knew there must be some explanation of the mystery, but what was it? He racked his brains to find a plausible solution. But the more he thought about it, the more uncertain he became, until at last he came to a resolution.
"Here I am," he thought, "racking my wits over this matter, and about all I do is just guess work, after all. The best thing I can do is get permission to go to the town, find that alley and see if I can't run across some clue that was lacking the last time I was there."
Having reached this resolve, he lost no time in acting on it, and readily securing the desired permission, he set off for the town. This he soon reached, and walked at a smart pace through the quaint, well-kept streets.
Going along one broad avenue he came suddenly face to face with the man from whom he had taken away the cane, whom he had since learned was a famous German physician, a well known character throughout the war. The latter, however, was so preoccupied that he took no notice of Frank. His thoughts, whatever they were, appeared to be pleasant, for as he walked he smiled to himself and softly rubbed his hands together, as one well pleased with the course of events.