A dishevelled figure stood by the boxes, revolver in hand—it was Bridgers, the man he had left strapped and bound in the "ambulance-room," and Beale cursed the folly which had induced him to leave the revolver behind.

"I'll fix you—you brute!" screamed Bridgers, "get away from him—ah!"

Beale's hand flew up, a pencil of flame quivered and again the vault trembled to the deafening report.

But Bridgers had dropped to cover. Again he shot, this time with unexpected effect. The bullet struck the fuse-box on the opposite wall and all the lights went out.

Beale was still holding the glass tube, and this Milsom had seen. Quick as thought he hurled himself upon the detective, his big, powerful hands gripped the other's wrist and wrenched it round.

Beale set his teeth and manoeuvred for a lock grip, but he was badly placed, pressed as he was against the edge of the bench. He felt van Heerden's fingers clawing at his hand and the tube was torn away.

Then somebody pulled the revolver from the other hand and there was a scamper of feet. He groped his way through the blackness and ran into the pile of boxes. A bullet whizzed past him from the half-crazy Bridgers, but that was a risk he had to take. He heard the squeak of an opening door and stumbled blindly in its direction. Presently he found it. He had watched the other men go out and discovered the steps—two minutes later he was in the street.

There was no sign of either of the two men. He found a policeman after he had walked half a mile, but that intelligent officer could not leave his beat and advised him to go to the police station. It was an excellent suggestion, for although the sergeant on duty was wholly unresponsive there was a telephone, and at the end of the telephone in his little Haymarket flat, a Superintendent McNorton, the mention of whose very name galvanized the police office to activity.

"I have found the factory I've been looking for, McNorton," said Beale. "I'll explain the whole thing to you in the morning. What I want now is a search made of the premises."

"We can't do that without a magistrate's warrant," said McNorton's voice, "but what we can do is to guard the premises until the warrant is obtained. Ask the station sergeant to speak on the 'phone—by the way, how is Miss Cresswell, better, I hope?"

"Much better," said the young man shortly.

It was unbelievable that she could ever fill his heart with the ache which came at the mention of her name.

He made way for the station sergeant and later accompanied four men back to the laboratory. They found all the doors closed. Beale scaled the wall but failed to find a way in. He rejoined the sergeant on the other side of the wall.

"What is the name of this street?" he asked.

"Playbury Street, sir—this used to be Henderson's Wine Vaults in my younger days."

Beale jotted down the address and finding a taxi drove back to the police station, wearied and sick at heart.

He arrived in time to be a witness to a curious scene. In the centre of the charge-room and facing the sergeant's desk was a man of middle age, shabbily dressed, but bearing the indefinable air of one who had seen better days. The grey hair was carefully brushed from the familiar face and gave him that venerable appearance which pale eyes and a pair of thin straight lips (curled now in an amused smile) did their best to discount.

By his side stood his captor, a station detective, a bored and apathetic man.

"It seems," the prisoner was saying, as Stanford Beale came noiselessly into the room, "it seems that under this detestable system of police espionage, a fellow may not even take a walk in the cool of the morning."

His voice was that of an educated man, his drawling address spoke of his confidence.

"Now look here, Parson," said the station sergeant, in that friendly tone which the police adopt when dealing with their pet criminals, "you know as well as I do that under the Prevention of Crimes Act you, an old lag, are liable to be arrested if you are seen in any suspicious circumstances—you oughtn't to be wandering about the streets in the middle of the night, and if you do, why you mustn't kick because you're pinched—anything found on him, Smith?"

"No, sergeant—he was just mouching round, so I pulled him in."

"Where are you living now, Parson?"

The man with extravagant care searched his pockets.

"I have inadvertently left my card-case with my coiner's outfit," he said gravely, "but a wire addressed to the Doss House, Mine Street, Paddington, will find me—but I don't think I should try. At this moment I enjoy the protection of the law. In four days' time I shall be on the ocean—why, Mr. Beale?"

Mr. Beale smiled.

"Hullo, Parson—I thought you had sailed to-day."

"The first-class berths are all taken and I will not travel to Australia with the common herd."

He turned to the astonished sergeant.

"Can I go—Mr. Beale will vouch for me?"

As he left the charge-room he beckoned the detective, and when they were together in the street Beale found that all the Parson's flippancy had departed.

"I'm sorry I got you into that scrape," he said seriously. "I ought to have been unfrocked, but I was sentenced for my first crime under an assumed name. I was not attached to any church at the time and my identity has never been discovered. Mr. Beale," he went on with a quizzical smile, "I have yet to commit my ideal crime—the murder of a bishop who allows a curate to marry a wife on sixty pounds a year." His face darkened, and Beale found himself wondering at the contents of the tragic years behind the man. Where was the wife...?

"But my private grievances against the world will not interest you," Parson Homo resumed, "I only called you out to—well, to ask your pardon."

"It was my own fault, Homo," said Beale quietly, and held out his hand. "Good luck—there may be a life for you in the new land."

He stood till the figure passed out of sight, then turned wearily toward his own rooms. He went to his room and lay down on his bed fully dressed. He was aroused from a troubled sleep by the jangle of the 'phone. It was McNorton.

"Come down to Scotland House and see the Assistant-Commissioner," he said, "he is very anxious to hear more about this factory. He tells me that you have already given him an outline of the plot."

"Yes—I'll give you details—I'll be with you in half an hour."

He had a bath and changed his clothes, and breakfastless, for the woman who waited on him and kept his flat and who evidently thought his absence was likely to be a long one, had not arrived. He drove to the grim grey building on the Thames Embankment.

Assistant-Commissioner O'Donnel, a white-haired police veteran, was waiting for him, and McNorton was in the office.

"You look fagged," said the commissioner, "take that chair—and you look hungry, too. Have you breakfasted?"

Beale shook his head with a smile.

"Get him something, McNorton—ring that bell. Don't protest, my good fellow—I've had exactly the same kind of nights as you've had, and I know that it is grub that counts more than sleep."

He gave an order to an attendant and not until twenty minutes later, when Beale had finished a surprisingly good meal in the superintendent's room, did the commissioner allow the story to be told.

"Now I'm ready," he said.

"I'll begin at the beginning," said Stanford Beale. "I was a member of the United States Secret Service until after the war when, at the request of Mr. Kitson, who is known to you, I came to Europe to devote all my time to watching Miss Cresswell and Doctor van Heerden. All that you know.

"One day when searching the doctor's rooms in his absence, my object being to discover some evidence in relation to the Millinborn murder, I found this."

He took a newspaper cutting from his pocket-book and laid it on the table.

"It is from El Impartial, a Spanish newspaper, and I will translate it for you.

"'Thanks to the discretion and eminent genius of Dr. Alphonso Romanos, the Chief Medical Officer of Vigo, the farmers of the district have been spared a catastrophe much lamentable' (I am translating literally). 'On Monday last, SeÑor Don Marin Fernardey, of La Linea, discovered one of his fields of corn had died in the night and was already in a condition of rot. In alarm, he notified the Chief of Medicines at Vigo, and Dr. Alphonso Romanos, with that zeal and alacrity which has marked his acts, was quickly on the spot, accompanied by a foreign scientist. Happily the learned and gentle doctor is a bacteriologist superb. An examination of the dead corn, which already emitted unpleasant odours, revealed the presence of a new disease, the verde orin (green rust). By his orders the field was burnt. Fortunately, the area was small and dissociated from the other fields of SeÑor Fernardey by wide zanzas. With the exception of two small pieces of the infected corn, carried away by Dr. Romanos and the foreign medical-cavalier, the pest was incinerated.'"

"The Foreign Medical-Cavalier," said Beale, "was Doctor van Heerden. The date was 1915, when the doctor was taking his summer holiday, and I have had no difficulty in tracing him. I sent one of my men to Vigo to interview Doctor Romanos, who remembers the circumstances perfectly. He himself had thought it wisest to destroy the germ after carefully noting their characteristics, and he expressed the anxious hope that his whilom friend, van Heerden, had done the same. Van Heerden, of course, did nothing of the sort. He has been assiduously cultivating the germs in his laboratory. So far as I can ascertain from Professor Heyler, an old German who was in van Heerden's service and who seems a fairly honest man, the doctor nearly lost the culture, and it was only by sending out small quantities to various seedy scientists and getting them to experiment in the cultivation of the germ under various conditions that he found the medium in which they best flourish. It is, I believe, fermented rye-flour, but I am not quite sure."

"To what purpose do you suggest van Heerden will put his cultivations?" asked the commissioner.

"I am coming to that. In the course of my inquiries and searchings I found that he was collecting very accurate data concerning the great wheatfields of the world. From the particulars he was preparing I formed the idea that he intended, and intends, sending an army of agents all over the world who, at a given signal, will release the germs in the growing wheat."

"But surely a few germs sprinkled on a great wheatfield such as you find in America would do no more than local damage?"

Beale shook his head.

"Mr. O'Donnel," he said soberly, "if I broke a tube of that stuff in the corner of a ten-thousand-acre field the whole field would be rotten in twenty-four hours! It spreads from stalk to stalk with a rapidity that is amazing. One germ multiplies itself in a living cornfield a billion times in twelve hours. It would not only be possible, but certain that twenty of van Heerden's agents in America could destroy the harvests of the United States in a week."

"But why should he do this—he is a German, you say—and Germans do not engage in frightfulness unless they see a dividend at the end of it."

"There is a dividend—a dividend of millions at the end of it," said Beale, graver, "that much I know. I cannot tell you any more yet. But I can say this: that up till yesterday van Heerden was carrying on the work without the aid of his Government. That is no longer the case. There is now a big syndicate in existence to finance him, and the principal shareholder is the German Government. He has already spent thousands, money he has borrowed and money he has stolen. As a side-line and sheerly to secure her money he carried off John Millinborn's heiress with the object of forcing her into a marriage."

The commissioner chewed the end of his cigar.

"This is a State matter and one on which I must consult the Home Office. You tell me that the Foreign Office believe your story—of course I do, too," he added quickly, "though it sounds wildly improbable. Wait here."

He took up his hat and went out.

"It is going to be a difficult business to convict van Heerden," said the superintendent when his chief had gone, "you see, in the English courts, motive must be proved to convict before a jury, and there seems no motive except revenge. A jury would take a lot of convincing that a man spent thousands of pounds to avenge a wrong done to his country."

Beale had no answer to this. At the back of his mind he had a dim idea of the sheer money value of the scheme, but he needed other evidence than he possessed. The commissioner returned soon after.

"I have been on the 'phone to the Under-Secretary, and we will take action against van Heerden on the evidence the factory offers. I'll put you in charge of the case, McNorton, you have the search-warrant already? Good!"

He shook hands with Beale.

"You will make a European name over this, Mr. Beale," he said.

"I hope Europe will have nothing more to talk about," said Beale.

They passed back to McNorton's office.

"I'll come right along," said the superintendent. He was taking his hat from a peg when he saw a closed envelope lying on his desk.

"From the local police station," he said. "How long has this been here?"

His clerk shook his head.

"I can't tell you, sir—it has been there since I came in."

"H'm—I must have overlooked it. Perhaps it is news from your factory."

He tore it open, scanned the contents and swore.

"There goes your evidence, Beale," he said.

"What is it?" asked Beale quickly.

"The factory was burned to the ground in the early hours of the morning," he said. "The fire started in the old wine vault and the whole building has collapsed."

The detective stared out of the window.

"Can we arrest van Heerden on the evidence of Professor Heyler?"

For answer McNorton handed him the letter. It ran:

"From Inspector-in-charge, S. Paddington, to Supt. McNorton. Factory in Playbury St. under P.O. (Police Observation) completely destroyed by fire, which broke out in basement at 5.20 this morning. One body found, believed to be a man named Heyler."