I think he must be an old lion to outwit Tarzan for so long.

"But what brings you into Tarzan's country, Doctor? I hope it is only a neighborly visit and that no trouble has come to my good friend, though your appearance belies my hope."

"I, too, wish that it were nothing more than a friendly call," said von Harben, "but as a matter of fact I am here to seek your help because I am in trouble--very serious trouble, I fear."

"Do not tell me that the Arabs have come down again to take slaves or to steal ivory, or is it that the leopard men are waylaying your people upon the jungle trails at night?"

"No, it is neither the one nor the other. I have come to see you upon a more personal matter. It is about my son, Erich. You have never met him."

"No," said Tarzan; "but you are tired and hungry. Let your men make camp here. My evening meal is ready; while you and I eat you shall tell me how Tarzan may serve you."

As the Waziri, at Tarzan's command, assisted von Harben's men in making their camp, the doctor and the ape-man sat cross-legged upon the ground and ate the rough fare that Tarzan's Waziri cook had prepared.

Tarzan saw that his guest's mind was filled with the trouble that had brought him in search of the ape-man, and so he did not wait until they had finished the meal to reopen the subject, but urged von Harben to continue his story at once.

"I wish to preface the real object of my visit with a few words of explanation," commenced von Harben. "Erich is my only son. Four years ago, at the age of nineteen, he completed his university course with honors and received his first degree. Since then he has spent the greater part of his time in pursuing his studies in various European universities, where he has specialized in archaeology and the study of dead languages. His one hobby, outside of his chosen field, has been mountain climbing and during succeeding summer vacations he scaled every important Alpine peak.

"A few months ago he came here to visit me at the mission and immediately became interested in the study of the various Bantu dialects that are in use by the several tribes in our district and those adjacent thereto.

"While pursuing his investigation among the natives he ran across that old legend of The Lost Tribe of the Wiramwazi Mountains, with which we are all so familiar. Immediately his mind became imbued, as have the minds of so many others, with the belief that this fable might have originated in fact and that if he could trace it down he might possibly find descendants of one of the lost tribes of Biblical history."

"I know the legend well," said Tarzan, "and because it is so persistent and the details of its narration by the natives so circumstantial, I have thought that I should like to investigate it myself, but in the past no necessity has arisen to take me close to the Wiramwazi Mountains."

"I must confess," continued the doctor, "that I also have had the same urge many times. I have upon two occasions talked with men of the Bagego tribe that live upon the slopes of the Wiramwazi Mountains and in both instances I have been assured that a tribe of white men dwells somewhere in the depths of that great mountain range. Both of these men told me that their tribe has carried on trade with these people from time immemorial and each assured me that he had often seen members of The Lost Tribe both upon occasions of peaceful trading and during the warlike raids that the mountaineers occasionally launched upon the Bagego.

"The result was that when Erich suggested an expedition to the Wiramwazi I rather encouraged him, since he was well fitted to undertake the adventure. His knowledge of Bantu and his intensive, even though brief, experience among the natives gave him an advantage that few scholars otherwise equipped by education to profit by such an expedition would have, while his considerable experience as a mountain climber would, I felt, stand him in good stead during such an adventure.

"On the whole I felt that he was an ideal man to lead such an expedition, and my only regret was that I could not accompany him, but this was impossible at the time. I assisted him in every way possible in the organization of his safari and in equipping and provisioning it.

"He has not been gone a sufficient length of time to accomplish any considerable investigation and return to the mission, but recently a few of the members of his safari were reported to me as having returned to their villages. When I sought to interview them they avoided me, but rumors reached me that convinced me that all was not well with my son. I therefore determined to organize a relief expedition, but in all my district I could find only these few men who dared accompany me to the Wiramwazi Mountains, which, their legends assure them, are inhabited by malign spirits--for, as you know, they consider The Lost Tribe of the Wiramwazi to be a band of bloodthirsty ghosts. It became evident to me that the deserters of Erich's safari had spread terror through the district.

"Under the circumstances I was compelled to look elsewhere for help and naturally I turned, in my perplexity, to Tarzan, Lord of the Jungle. Now you know why I am here."

"I will help you, Doctor," said Tarzan, after the other had concluded.

"Good!" exclaimed von Harben; "but I knew that you would. You have about twenty men here, I should judge, and I have about fourteen. My men can act as carriers, while yours, who are acknowledged to be the finest fighting men in Africa, can serve as askaris. With you to guide us we can soon pick up the trail and with such a force, small though it be, there is no country that we cannot penetrate."

Tarzan shook his head. "No, Doctor," he said, "I shall go alone. That is always my way. Alone I may travel much more rapidly and when I am alone the jungle holds no secrets from me--I shall be able to obtain more information along the way than would be possible were I accompanied by others. You know the jungle people consider me as one of themselves. They do not run away from me as they would from you and other men."

"You know best," said von Harben. "I should like to accompany you. I should like to feel that I am doing my share, but if you say no I can only abide by your decision."

"Return to your mission, Doctor, and wait there until you hear from me."

"And in the morning you leave for the Wiramwazi Mountains?" asked von Harben.

"I leave at once," said the ape-man.

"But it is already dark," objected von Harben.

"There is a full moon and I wish to take advantage of it," explained the other. "I can lie up in the heat of the day for what rest I need." He turned and called Muviro to him.