The creature had gorged itself on dreamshit for nearly a fortnight, growing and growing. When it had reached three feet in length, Isaac had nervously stopped feeding it. Its cage was getting much too small. That would have to be the full extent of its size. It had spent the next day or two wandering around hopefully in its little space, waving its nose in the air. Since then it seemed to have resigned itself to the fact that it would get no more food. Its original desperate hunger had subsided.

It was not moving very much, just shifting around now and then, undulating once or twice the width of the cage, stretching as if yawning. For the most part it just sat and pulsed slightly in and out, with breath or heartbeat or what, Isaac did not know. It looked healthy enough. It looked as if it was waiting.

Sometimes, as he had dropped the gobs of dreamshit into the caterpillar’s eager mandibles, Isaac had found himself reflecting on his own experience with the drug with a faint, querulous longing. This was not the delusion of nostalgia. Isaac vividly remembered the sense of being awash in filth; of being sullied at the most profound level; the nauseating, disorientating sickness; the panicked confusion of losing himself in a welter of emotion, and losing the confusion, and mistaking it for another mind’s invading fears . . . And yet, despite the vehemence of those recollections, he found himself eyeing his caterpillar’s breakfasts with a speculative air—perhaps even a hungry one.

Isaac was very disturbed by these feelings. He had always been unashamedly cowardly when it came to drugs. As a student, there had been plenty of loose, smelly fogweed cigarillos, of course, and the inane giggles that went with that. But Isaac had never had the stomach for anything stronger. These inchoate rumblings of a new appetite did nothing to allay his fears. He did not know how addictive dreamshit was, if at all, but he sternly refused to give in to those faint stirrings of curiosity.

The dreamshit was for his caterpillar, and for it alone.

Isaac channelled his curiosity from sensual into intellectual currents. He knew only two chymists personally, both unutterable prudes with whom he would no more raise the question of illegal drugs than he would dance naked down the middle of Tervisadd Way. Instead, he raised the subject of dreamshit in the louche taverns of Salacus Fields. Several of his acquaintances turned out to have sampled the drug, and a few were regular users.