again.  Professor Carnes is my last one, though nobody would be more astonished than he to know that he is regarded in the light of an old Israelitish Memorial stone.  You will not have such frequent letters from me after this, as I shall be so busy.  But Jack says he will attend to my correspondence.  He is beginning to write a little every day.  Yesterday he wrote to Betty.  He has enjoyed her letters so much, telling about her lovely time up in the Maine woods.  I am so glad you are to have a vacation, too.  So no more at present from your happy little sister.”

Like all people who are limited to one hobby, and who pursue one line of study for years regardless of other interests, Professor Carnes took little notice of anything outside of his especial work.  If Mary had been a new kind of bug he would have studied her with profound interest, spending days in learning her peculiarities, and sparing no pains in classifying her and assigning her to the place she occupied in the great plan of creation.  But being only a human being she attracted his attention only so far as she contributed to the success of his work.

He would go tramping through the woods wherever she led, only vaguely aware of the fact that she had enlisted half a dozen small boys in her service, and that she was turning them into enthusiastic young naturalists before his very eyes.  She was not doing this consciously, however.  Her motive for inviting them on these expeditions, was simply to include Norman and his friends in her own enjoyment of the summer woods.  It was so easy to turn each excursion into a picnic, to build a fire near some spring and set out a simple lunch that seemed a feast of the gods to voracious boyish appetites.

The goodly smell of corn, roasting in the ashes, or fresh fish sizzling on hot stones gave a charm to the learning of wood-lore that it never could have possessed otherwise.  At first with the heedlessness of city-bred boys, they crashed through the under-brush with unseeing eyes, and unhearing ears, but it was not long until they had learned the alertness of young Indians, following by signs of bark and leaf and fallen feather, trails more interesting than any detective story.

Gradually the old professor, aroused to the fact that they were valuable assistants, began to take some notice of them.  They awakened memories of his own barefooted boyhood, and sometimes when he had had a particularly successful morning, he threw off his habitual abstraction, and as Mary reported to Jack, was “as human as anybody.”

It seemed, too, that at these times he saw Mary in a new light; saw her as the boys did, fearless as one of themselves, tireless as a squaw, and a happy-go-lucky comrade who could turn the most ordinary occasion into a jolly outing.  Her knack of inventing substitutes when he had left some necessary article at home filled him with mild wonder.  He came to believe that her resources were unlimited;