The filaments were there, clear and distinct.
He turned on the little tape recorder that had been part of Chris' equipment and set the microphone where he could dictate into it without stopping to make clumsy notes. He readjusted the focus carefully, carrying on a running commentary.
Then he gasped. Each of the little filaments carried three tiny darker sections; each was a cell, complete in itself, with the typical Martian triple nucleus.
He put a film with a tiny section of the nerve tissue from a corpse into the chamber next, and again a quick glance at the screen was enough. The filaments were there, thickly crowded among nerve cells. They did travel along the nerves to reach the base of the brain before the larger lump could form.
A specimen from one of the black specks was even more interesting. The filaments were there, but some were changed or changing into tiny, round cells, also with the triple dark spots of nuclei. Those must be the final form that was released to infect others. Probably at first these multiplied directly in epithelial tissue, so that there was a rapid contagion of infection. Eventually, they must form the filaments that invaded the nerves and caused the brief bodily reaction that was Selznik's migraine. Then the body adapted to them and they began to incubate slowly, developing into the large cells he had first seen. When "ripe", the big cells broke apart into millions of the tiny round ones that went back to the nerve endings, causing the black spots and killing the host.
He knew his enemy now, at least.
He reached for the controls, increasing the magnification. He would lose resolution, but he might find something more at the extreme limits of the mike.
Something wet and cold gushed into his face. He jerked back, trying to wipe it off, but it was already evaporating, and there was a thick, acrid odor in the cab. He grabbed for his aspirator, then tried to reach the airlock. But paralysis was already spreading through him, and he toppled to the floor before he could escape.
When he came to, it was morning outside, and Chris was waiting inside the cab with two big Lobby policemen. A hypo in her hand must have been what revived him.
She touched the electron microscope with something like affection. "The Lobby technicians did a good job on this, don't you think, Dan? I warned you, but you wouldn't listen. And now we've even got your own taped words to prove you were doing forbidden research. Fool!"