being in the background. "I am glad to see
you. I want----"

He made a sudden motion toward the smiling, Red Cross nurse, and
instinctively she stepped back, with something of a look of alarm on
her face.

"One moment--please!" exclaimed the professor. "There is a most
beautiful and rare butterfly on your apron. I just want it for my
collection," and, a moment later, he had safe in one of his wire boxes
the fluttering _Papilio_.

"Oh, how beautiful!" murmured the nurse. "What are you going to do
with the poor thing?"

"Preserve it so that others may gaze on its beauty," answered the
professor with a bow. "It will also aid me in my studies. This
particular butterfly is one I have long sought, because of the
peculiar markings. It is most lucky that I came here to-day."

"Well, it might have been unlucky if you had happened to be hit by one
of the German air bombs," said Jerry. "But we're glad to see you. We
have good news for you about those two girls."

"Yes, so I understand from your letters. So that janitor has seen
them. Well, now I must follow them up and give them their share of the
fortune. I came on as soon as I could after hearing from you boys. I
thank you for having my interests at heart. Now where can I see this
Nick Schmouder and have a talk with him?"

The camp where the German prisoners were detained was not many miles
back of the hospital where Jerry had recovered from his wounds, and,
as he would be able to travel the next day, and as Bob and Ned could
get furloughs, it was decided that the four should make up a party and
seek out the former janitor, so that the professor might hear, at
first hand, all there was to be said.

These arrangements having been made, transportation provided and the
necessary permissions having been secured, the professor and the
three Motor Boys, several hours later, sat down to have a long chat
and exchange experiences. Professor Snodgrass told how he was
progressing with his work of studying the effects of battle noises on
insects, and the boys related their stories of fighting and battles.

"And we thought old Jerry was gone when we saw him go down outside the
dugout where we captured Schmouder," finished Ned, as a climax to his
story.

"I thought so myself," admitted the tall lad. "But I'm as well as
ever, and next week I'll be fighting again. What are your plans,
Professor?"

"I must try to find those two young ladies. The military authorities
have been ver