Bruce knew, too, that the nurse did not belong to his loved friends of the Red Cross. For his uncanny power of scent told him the garments worn by the impostor belonged to some one else. To mere humans, a small and slender man, who can act, and who dons woman's garb, is a woman. To any dog, such a man is no more like a woman than a horse with a lambskin saddle-pad is a lamb. He is merely a man who is differently dressed from other men--even as this man who had chirped to Bruce, from the church steps, was no less a man for the costume in which he had swathed his body. Any dog, at a glance and at a sniff, would have known that. Women, for one thing, do not usually smoke dozens of rank cigars daily for years, until their flesh is permeated with the smell of tobacco. A human could not have detected such a smell--such a MAN-smell,--on the person who had chirped to Bruce. Any dog, twenty feet away, would have noticed it, and would have tabulated the white-clad masquerader as a man. Nor do a woman's hair and skin carry the faint but unmistakable odor of barracks and of tent-life and of martial equipment, as did this man's. The masquerader was evidently not only a man but a soldier. Dogs,--high-strung dogs,--do not like to have tricks played on them; least of all by strangers. Bruce seemed to take the nurse-disguise as a personal affront to himself. Then, too, the man was not of his own army. On the contrary, the scent proclaimed him one of the horde whom Bruce's friends so manifestly hated--one of the breed that had more than once fired on the dog. Diet and equipment and other causes give a German soldier a markedly different scent, to dogs' miraculously keen nostrils,--and to those of certain humans,--from the French or British or American troops. War records prove this. Once having learned the scent, and having learned to detest it, Bruce was not to be deceived. For all these reasons he had snarled loathingly at the man in white. For these same reasons he could not readily forget the incident, but continued every now and then to glance curiously across toward the church. Presently,--not relishing the rebukes of the friends who had heretofore pestered him by overmuch petting,--the collie arose quietly from his couch of trampled earth at the foot of the stone bench and strolled back across the street. Most of the men were too busy, talking, to note Bruce's departure. But Sergeant Mahan caught sight of him just as the dog was mounting the last of the steps leading into the church. As a rule, when Bruce went investigating, he walked carelessly and with his tail slightly a-wag. Now his tail was stiff as an icicle, and he moved warily, on the tips of his toes. His tawny-maned neck was low. Mahan, understanding dogs, did not like the collie's demeanor. Remembering that the nurse had entered the church a few minutes earlier, the Sergeant got to his feet and hastily followed Bruce.