Children of the Lens by E.E. Smith

While Kathryn Kinnison was working with her father in the hyperspatial tube and with Mentor of Arisia, and while Camilla and Tregonsee were sleuthing the inscrutable "X", Constance was also at work. Although she lay flat upon her back, not moving a muscle, she was working as she had never worked before. Long since she had put her indetectable speedster into the control of a director-by-chance. Now, knowing nothing and caring less of where she and her vessel might be or might go, physically completely relaxed, she drove her "sensories" out to the full limit of their prodigious range and held them there for hour after hour. Worsel-like, she was not consciously listening for any particular thing; she was merely increasing her already incredibly vast store of knowledge.

One hundred percent receptive, attached to and concerned with only the brain of her physical body, her mind sped at large sampling, testing, analyzing, cataloguing every item with which its most tenuous fringe came in contact. Through thousands of solar systems that mind went; millions upon millions of entities either did or did not contribute something worth while.