While Bess was thus employed, her colleague had his hands full in London. On arriving at Paddington, Herrick drove directly to the West Kensington Flat. It was closed, and the porter explained that Mr. Joyce had been away for some weeks.

"Ah, that is a pity," said Dr. Jim with a grim smile. "I wished to see him most particularly."

"I expect him back shortly sir," said the man.

"Ah! Has he written to fix the date of his return?"

"Not yet sir. But Mr. Joyce never remains away more than a month or two."

"He may change his habits this time."

"I don't think so sir. Shall I tell him you called sir?"

"No. You need not go so far as that. When he comes home just send a wire to that address. And this for yourself."

The porter, a venal creature in uniform, looked at the half sovereign and the address of the Guelph Hotel in Jermyn Street. He promised faithfully to send a wire the moment Mr. Joyce returned, and Dr. Jim went away, very well satisfied that he had done right in having Robin watched. "Damned little scoundrel!" growled Herrick. "What is the use of sparing him? But that he is in the hands of a stronger villain, I would lay him by the heels straight off. But I shall deal with Santiago this time. I expect he and Joyce are plotting together in some hole."

In another hour Herrick was climbing a flight of dingy stairs in the neighbourhood of the Strand. He stopped at the second landing and before a door, which bore the name of Kidd, Belcher & Co, Private Inquiry Office. On entering he was confronted by a dirty undersized boy. Kidd was absent on business, but Belcher was in, and on giving his card, Dr. Jim was shown into the next room. Here at a table near the window sat a man. That is he stood on two legs, he was neatly dressed, and he talked in a prim precise voice. But going by his face he was a ferret. The long face and nose, the broad forehead and small receding chin, and above all the red-rimmed eyes without eyebrows or eyelashes. All this made him look very much like a ferret. And his nature was also of the beast. He was a sly, silent, cunning tracker, relentless when once he had hunted down his prey. A dangerous man, a deadly man, who had elected to place himself on the side of the law, as offering the better price. Had he chosen to be one of the great criminal profession, Mr. Belcher would have been a dangerous opponent to the police. Luckily he found that honesty paid better than roguery, therefore he was at the disposal of Dr. Jim, for the watching of Santiago and Joyce. He talked freely on this point. "It's all right sir," he said in his whispering voice and arranging his neat white tie. "Kidd caught him at the Paddington station, and followed him to Pimlico."

"Oh, he is in Pimlico is he?"

"Watched by three boys, and Kidd himself. Four kids I call them," said Mr. Belcher with a silent laugh. "You see sir that Mexican gent prefers to live at Pimlico because it is near the Gambling Club. We need not mention names sir, as I have an interest in that club and don't want the police to know of it. I hunt with the hounds and run with the fox you see," and Belcher gave another of his silent laughs.

"Humph!" said Jim taking no notice of the joke, "so Joyce is at Santiago's lodgings is he?"

"Drove straight therefrom Paddington, and has not been out of doors since. The Don has been sir. He never thinks you are after _him_."

"I fancy he has rather a contempt for my brains," said Jim. "However we shall see about that. I'll go to those lodgings."

"Would you mind telling me what the Mexican has done sir?"

"I would mind very much Mr. Belcher. When I want to tell you my business you won't have to help me. It is a private matter. But later on there may be something in it likely to pay you. At present all I want you to do is to keep an eye on Joyce and Santiago. I will pay you well for it."

"Yes sir, thank you, sir. Excuse my curiosity. Quite professional."

"No doubt; but you will make more money by asking no questions. If things are as I suspect with these two it will put a lot of cash into your pockets. Meanwhile, hold your tongue."

"Very good Dr. Herrick," said the ferret meekly, "so long as you know your business, I don't need to teach it to you. But you know our firm. We are straight."

"So long as you are paid. Otherwise you prefer to keep gambling saloons unknown to the police. Oh, never fear man, I shall say nothing. By the way, lend me a revolver:"

"Ha!" said the ferret with sudden interest, "is it as bad as that?"

"I think so. One at least of the two will show fight, and it won't be the man you followed from Paddington. You had better come with me Belcher. I want to know if the coast is clear. If the two catch sight of me from the window, they may clear out. While I am talking to them, you and Kidd can remain outside. If you hear a shot, rush up with the nearest policeman. But I won't fire unless I am driven to it."

"Going to shoot one of them Dr. Herrick?" said Belcher producing a very serviceable weapon which Jim slipped into his breast pocket.

"Not unless either one draws on me. It is the Mexican I fear. But it is the more likely I shall only fire the revolver by way of a signal. You know what you have to do?"

"Yes sir," said the ferret with something of admiration in his whisper, "you ought to have been in our profession doctor. You provide against every chance."

"Except sudden death," laughed Jim as they went down the dingy stairs, "I have a tough article to deal with in that Santiago. Do you know anything about him Belcher."

The ferret shook his head and waved a neat umbrella to a passing hansom. "Not much sir," he replied, "he's been in England over six months, and always in the same lodgings. He has money but not too much of it. I got to know him at the club, and he gambled so high and won so much that I made it my business to look after him. But I could find out nothing to get the whip hand of him, sir."

"Mr. Joyce goes to your club also?"

"Yes sir. I told you so when you called to see me first. I knew the name at once. Kidd knows him too, but he doesn't know Kidd. That was why I sent Kidd to Paddington. He's a fool, sir."

"True enough," replied Herrick dryly, "but even a fool can become dangerous in the hands of an unscrupulous scoundrel like Santiago. Oh, I do not know anything against him," added Herrick seeing the ferret's eyes twinkle. "I am only going by the little I do know."

"Not enough to jail him I suppose, sir?"

"Not yet, but there might be soon," replied Jim, glancing sideways at his neat companion. He well knew that Belcher and Kidd liked to know secrets in order to extort blackmail. A dangerous pair; but Jim knew how to deal with them. They were rather afraid of Jim. He knew too much.

Herrick had become acquainted with the ferret through having saved the life of his small daughter, and as this child was the apple of the man's eye, he adored Jim and was in the habit of speaking to him more freely than he otherwise would have done. Therefore Jim got to know more about the Private Inquiry Firm than was altogether wise. However, he could keep his mouth shut, and, as at present, he sometimes found the pair useful. But the connection was not a pleasant one, even so, and Herrick was wont to comfort himself with the reflection that when dirty work has to be done, no man can be nice in the choice of his instruments.

Directed by the ferret, the cab stopped at the corner of a Pimlico street in a quiet neighbourhood. There he left the doctor in the cab, and went along to reconnoitre. In ten minutes he came back.

"The Mexican has gone out," said Belcher, "he has been away an hour. But Joyce is in the sitting-room. Kidd saw his face two or three times at the window. If you creep along the street under the house he won't be able to see you."

"Right you are," said Dr. Jim climbing down, and paying off the cab--lavishly because he did not want a disturbance, "you wait outside both of you and keep an eye on the policeman. When you hear a shot"--

"You needn't tell me twice Dr. Herrick," said Belcher, his professional pride wounded. "Off you go sir, I'll stop hereabouts and whistle if the Mexican comes along. He doesn't know my real business."

"Jim nodded, and walked along to number forty-three, where--as Belcher told him Santiago had rooms on the first floor. On the opposite side of the street he saw Kidd with a green shade and picturesquely attired in rags, playing the part of a pavement artist. At the end of the street three or four boys were playing marbles. No one would suspect that either man or boys were spies. Jim fingered his revolver, and rang the bell.

"I want to see Mr. Joyce," he said to the slattern who opened the door, "my name is Nuttall, and I come from Don Manuel Santiago."

The slattern suspecting nothing from this calm address conducted Jim up the stairs. She opened a door and gave the message to Robin. Herrick heard his voice telling her to show in Mr. Nuttall, and he guessed from the sound of it that Joyce was uneasy. The slattern pushed Jim to the door and then dropped down stairs rapidly. She wanted to get back to her novel, for her mistress was away for the afternoon.

"Well Joyce and how are you?"

Robin gave a kind of squeal like that of a trapped animal, and fell back into the chair from which he had risen to welcome Mr. Nuttall. His face grew white, his jaw dropped, and he collapsed into a limp heap. Fright so paralysed his tongue that he could not speak. Jim smiled politely and closed the door. Then he took a chair opposite to the wretched creature.

"You are a proper little scoundrel," he said in withering tones, "I am sorry to see you brought so low as this, Joyce."

"What do you want?" cried Robin flaming into sudden fury. "Have you not humiliated me enough, but that you must come after me----"

"To find you in hiding with Don Manuel. Go easy Joyce, and keep a civil tongue in your head."

"I'd like to kill you," he muttered, his face distorted with fury.

"I have no doubt you would, and I have also small doubt but that your friend Santiago will try."

"Do you want to see him?"

"And you. Yes. You told me such lies at Saxham, coached by Don Manuel I suppose, that I wish to talk to the two of you together."

"If you don't leave this place I will call the police."

"Do so by all means. I shall give you in charge when they appear. Come Joyce, don't be a fool! You have to sit down and do what I tell you."

Joyce resumed his seat and bit his fingers. "Santiago will kill you," he muttered viciously. "I hope he will!"

"Thank you; I see pity is wasted on a reptile like you. But see here," said Jim with sudden fierceness. "I am prepared for you and for the Mexican also. I have only to fire this," he showed the revolver "and the detectives who are waiting will co............