The Vulcan — that was the big spaceliner that was sailing tonight for Jupiter, with stops at Mars and Earth. Whatever interplanetary spy had been here was planning to leave Venus tonight on that ship!
But what was it that had been said about a braincase? Slowly his stunned brain rallied. The voice had said:
"Quick! To the Vulcan! I'll carry the braincase."
Suddenly into Rab Crane's confused mind shot a possible explanation.
He bent quickly over the dead body of Doctor Alph once more, flashed his ring-light on the shattered skull of the Venusian scientist. He gasped as he saw that his shocking surmise had been right.
There was no brain in the broken skull of Doctor Alph! The scientist's brain had been carefully removed by cunning surgery after the skull had been smashed by a blow. Or possibly the blow had been delivered after the operation so that no one would notice the horrible theft.
"God in heaven!" muttered Rab Crane. "Whoever came to get Doctor Alph's secret, got it — by stealing his brain!"
Rab Crane was aghast. He knew that in these days the removal of a living brain from a man's body, and keeping it living in special serum, was child's play to anyone versed in surgery.
And he knew, too, that such preserved, living brains could be made to think and remember; that they could be communicated with by microphonic and loudspeaker electrical connections to their hearing and speech nervecenters. Whoever had taken Doctor Alph's brain had come here intending to steal it, and had brought a special serum-case for its transportation!
And the brain-thief might be already aboard the Vulcan, ready to leave Venus with his ghastly loot. Once away from Venus, it would not take him long to make the living brain give up its secret, and that meant that the planet the thief served would acquire the dead scientist's terrible secret weapon!