I felt pretty tired and determined to make up for it by sleeping the next day. It was no use, however.

"Why, what's the matter, Mrs. Northrop?" I heard Kennedy ask as he opened our door the next morning, just as I had finished dressing.

He had admitted a young woman, who greeted us with nervous, wide-staring eyes.

"It's--it's about Archer," she cried, sinking into the nearest chair and staring from one to the other of us.

She was the wife of Professor Archer Northrop, director of the archeological department at the university. Both Craig and I had known her ever since her marriage to Northrop, for she was one of the most attractive ladies in the younger set of the faculty, to which Craig naturally belonged. Archer had been of the cla.s.s below us in the university. We had hazed him, and out of the mild hazing there had, strangely enough, grown a strong friendship.

I recollected quickly that Northrop, according to last reports, had been down in the south of Mexico on an archeological expedition. But before I could frame, even in my mind, the natural question in a form that would not alarm his wife further, Kennedy had it on his lips.

"No bad news from Mitla, I hope?" he asked gently, recalling one of the main working stations chosen by the expedition and the reported unsettled condition of the country about it. She looked up quickly.

"Didn't you know--he--came back from Vera Cruz yesterday?" she asked slowly, then added, speaking in a broken tone, "and--he seems--suddenly--to have disappeared. Oh, such a terrible night of worry! No word--and I called up the museum, but Doctor Bernardo, the curator, had gone, and no one answered. And this morning--I couldn't stand it any longer--so I came to you."

"You have no idea, I suppose, of anything that was weighing on his mind?" suggested Kennedy.

"No," she answered promptly.

In default of any further information, Kennedy did not pursue this line of questioning. I could not determine from his face or manner whether he thought the matter might involve another than Mrs. Northrop, or, perhaps, something connected with the unsettled condition of the country from which her husband had just arrived.

"Have you any of the letters that Archer wrote home?" asked Craig, at length.

"Yes," she replied eagerly, taking a little packet from her handbag. "I thought you might ask that. I brought them."

"You are an ideal client," commented Craig encouragingly, taking the letters. "Now, Mrs. Northrop, be brave. Trust me to run this thing down, and if you hear anything let me know immediately."

She left us a moment later, visibly relieved.

Scarcely had she gone when Craig, stuffing the letters into his pocket unread, seized his hat, and a moment later was striding along toward the museum with his habitual rapid, abstracted step which told me that he sensed a mystery.

In the museum we met Doctor Bernardo, a man slightly older than Northrop, with whom he had been very intimate. He had just arrived and was already deeply immersed in the study of some new and beautiful colored plates from the National Museum of Mexico City.

"Do you remember seeing Northrop here yesterday afternoon?" greeted Craig, without explaining what had happened.

"Yes," he answered promptly. "I was here with him until very late. At least, he was in his own room, working hard, when I left."

"Did you see him go?"

"Why--er--no," replied Bernardo, as if that were a new idea. "I left him here--at least, I didn't see him go out."

Kennedy tried the door of Northrop's room, which was at the far end, in a corner, and communicated with the hall only through the main floor of the museum. It was locked. A pa.s.s-key from the janitor quickly opened it.

Such a sight as greeted us, I shall never forget. There, in his big desk-chair, sat Northrop, absolutely rigid, the most horribly contorted look on his features that I have ever seen--half of pain, half of fear, as if of something nameless.

Kennedy bent over. His hands were cold.

Northrop had been dead at least twelve hours, perhaps longer. All night the deserted museum had guarded its terrible secret.

As Craig peered into his face, he saw, in the fleshy part of the neck, just below the left ear, a round red mark, with just a drop or two of now black coagulated blood in the center. All around we could see a vast amount of miscellaneous stuff, partly unpacked, partly just opened, and waiting to be taken out of the wrappings by the now motionless hands.

"I suppose you are more or less familiar with what Northrop brought back?" asked Kennedy of Bernardo, running his eye over the material in the room.

"Yes, reasonably," answered Bernardo. "Before the cases arrived from the wharf, he told me in detail what he had managed to bring up with him."

"I wish, then, that you would look it over and see if there is anything missing," requested Craig, already himself busy in going over the room for other evidence.

Doctor Bernardo hastily began taking a mental inventory of the stuff.

While they worked, I tried vainly to frame some theory which would explain the startling facts we had so suddenly discovered.

Mitla, I knew, was south of the city of Oaxaca, and there, in its ruined palaces, was the crowning achievement of the old Zapotec kings.

No ruins in America were more elaborately ornamented or richer in lore for the archeologist.

Northrop had brought up porphyry blocks with quaint grecques and much hieroglyphic painting. Already unpacked were half a dozen copper axes, some of the first of that particular style that had ever been brought to the United States. Besides the sculptured stones and the mosaics were jugs, cups, vases, little G.o.ds, sacrificial stones--enough, almost, to equip a new alcove in the museum.

Before Northrop was an idol, a hideous thing on which frogs and snakes squatted and coiled. It was a fitting piece to accompany the gruesome occupant of the little room in his long, last vigil. In fact, it almost sent a shudder over me, and if I had been inclined to the superst.i.tious, I should certainly have concluded that this was retribution for having disturbed the lares and penates of a dead race.

Doctor Bernardo was going over the material a second time. By the look on his face, even I could guess that something was missing.

"What is it?" asked Craig, following the curator closely.

"Why," he answered slowly, "there was an inscription--we were looking at it earlier in the day--on a small block of porphyry. I don't see it."

He paused and went back to his search before we could ask him further what he thought the inscription was about.

I thought nothing myself at the time of his reticence, for Kennedy had gone over to a window back of Northrop and to the left. It was fully twenty feet from the downward slope of the campus there, and, as he craned his neck out, he noted that the copper leader of the rain pipe ran past it a few feet away.

I, too, looked out. A thick group of trees hid the window from the avenue beyond the campus wall, and below us, at a corner of the building, was a clump of rhododendrons. As Craig bent over the sill, he whipped out a pocket lens.

A moment later he silently handed the gla.s.s to me. As nearly as I could make out, there were five marks on the dust of the sill.

"Finger-prints!" I exclaimed. "Some one has been clinging to the edge of the ledge."

"In that case," Craig observed quietly, "there would have been only four prints."

I looked again, puzzled. The prints were flat and well separated.

"No," he added, "not finger-prints--toe-prints."

"Toe-prints?" I echoed.

Before he could reply, Craig had dashed out of the room, around, and under the window. There, he was carefully going over the soft earth around the bushes below.

"What are you looking for?" I asked, joining him.

"Some one--perhaps two--has been here," he remarked, almost under his breath. "One, at least, has removed his shoes. See those shoe-prints up to this point? The print of a boot-heel in soft earth shows the position and contour of every nail head. Bertillon has made a collection of such nails, certain types, sizes, and shapes used in certain boots, showing often what country the shoes came from. Even the number and pattern are significant. Some factories use a fixed number of nails and arrange them in a particular manner. I have made my own collection of such prints in this country. These were American shoes.

Perhaps the clue will not lead us anywhere, though, for I doubt whether it was an American foot."

Kennedy continued to study the marks.