“How can I, Professor?” I asked, turning to meet his full face, and noticed that his dark, somewhat opaque brown irises had lights and gleams of carbuncle-crimson in them. “I have had Lady Clanbevan and her progeny under my occasional observation for years. The world grows older, if she doesn’t, and she has invariably a baby—toujours a new baby—to add to the charming illusion of young motherhood which she sustains so well. And now you tell me that she is a twenty-years’ widow with one child, who must be nearly of age—or it isn’t proper. You puzzle me painfully!”
“Would you care,” asked the Professor after a moment’s pause, “to drive back to Harley Street with me? I am, as you know, a vegetarian, so I will not tax your politeness by inviting you to lunch. But I have something in my laboratory I should wish to show you.”
“Of all things, I should like to come,” I said. “How many times haven’t I fished fruitlessly for an invitation to visit the famous laboratory where nearly twenty years ago——”
“I traced,” said the Professor, “the source of phenomena which heralded the evolution of the Röntgen Ray and the ultimate discovery of the radio-active salt they have christened radium. I called it protium twenty years ago, because of its various and protean qualities. Why did I not push on—perfect the discovery and anticipate Sir William C—— and the X——’s? There was a reason. You will understand it before you leave my laboratory.”
The Baby-Bunting stopped at the unfashionable end of Harley Street, in front of the dingy yellow house with the black front door, flanked by dusty boxes of mildewed dwarf evergreens, and the Professor, relieved of his fur-lined coat and cap, led the way upstairs as lightly as a boy. Two garret-rooms had been knocked together for a laboratory. There was a tiled furnace at the darker end of the long skylighted room thus made, and solid wooden tables much stained with spilt chemicals, were covered with scales, glasses, jars, and retorts—all the tools of chemistry. From one of the many shelves running round the walls, the Professor took down a circular glass flask and placed it in my hands. The flask contained a handful of decayed and moldy-looking wheat, and a number of peculiarly offensive-looking little beetles with tapir-like proboscides.
“The perfectly developed beetle of the Calandria granaria,” said the Professor, as I cheerfully resigned the flask, “a common British weevil, whose larvæ feed upon stored grain. Now look at this.” He reached down and handed me a precisely similar flask, containing another handful of grain, cleaner and sounder in appearance, and a number of grubs, sharp-ended chrysalis-like things buried in the grain, inert and inactive.
“The larvæ of Calandria granaria,” said the Professor, in his drawling monotone. “How long does it take to hatch the beetle from the grub? you ask. Less than a month. The perfect weevils that I have just shown you I placed in their flask a little more than three weeks back. The grubs you see in the flask you are holding, and which, as you will observe by their anxiety to bury themselves in the grain so as to avoid contact with the light, are still immature, I placed in the glass receptacle twenty years ago. Don’t drop the flask—I value it.”
“Professor!” I gasped.
“Twenty years ago,” repeated the Professor, delicately handling the venerable grubs, “I enclosed these grubs in this flask, with sufficient grain to fully nourish them and bring them to the perfect state. In another flask I placed a similar number of grubs in exactly the same quantity of wheat. Then for twenty-four hours I exposed flask number one to the rays emanating from what is now called radium. And as the electrons discharged from radium are obstructed by collision with air-atoms, I exhausted the air contained in the flask.” He paused.
“Then, when the grubs in flask number two hatched out,” I anticipated, “and the larvæ in flask number one remained stationary, you realized——”