The Biochem labs occupied a complete “building”--a structural unit shaped like a pie-slice with the first forkful already gone--a pumpkin pie, possibly, or any fallen custard filling that would provide for greater height at the outside than in the center. Eight such buildings extended from the central Mall to the crater walls, rising by stepped-back stories till the top two levels in each were single rows of rooms facing the transparent dome wall above the crater. These were, for the most part, living quarters, but in Bio even the top stories were taken over for lab space by now. Still, there was not room enough in the one building. The “Mars-bugs,” which had occupied perhaps one cubic meter in their sample boxes on the _Colombo_ twenty months earlier had been so carefully, prudently, frequently, and multi-experimentally proliferated in the meantime that a department which had once shared the single building with two other sections had now--and recently, nearly half of the growth having occurred in the past three months--overflowed into corners and corridors all through the Dome. There was a batch of cultures in Metallurgy being studied for “evolution-mutation” response to various mineral environments. With the assays and testing of (non-self-reproducing) Mars samples long finished in that department, and its original function in connection with rocket construction and propulsion become an economic dodo, the once-proudly _in_organic chemists turned eagerly to working with bugs. The hydroponics farm had suffered no such financial blight as had Metals and Fuels and other non-maintenance projects; but efficiency in the building known as the Farm had so minimized space requirements during eleven years of steadily increased personnel _and_ improved living standards, that one whole tank room was available--and thus put to use--for “farming” experiments with bugs. A section of Electronics was currently being cleared and remodeled for the cybernetic approach to a theoretical understanding of “controlled evolution” by construction of analog computers which might “act out” the mathematics that had to date eluded all other efforts at analytical understanding. As a matter of fact, the bugs had already, in one sense, overflowed the Dome itself. One farm-tank full had been “planted” in an open pavilion outside the walls, roofed against meteors, but incompletely enclosed: “The Shack” was the simplest way to conduct Moon-environment tests. * * * * * Lisa followed Thad Bourgnese down ramp after ramp in the Bio building, listening with half an ear as she was trailed through the upper levels where the Earth-normal atmosphere work was done, down to the glassed-off pressurized chambers near the crater floor where experiments were conducted by space-suited scientists in Mars-normal, or at least a half-dozen variant approximations of Mars-normal, atmosphere.