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."