The meaning of "the spaces" in the sentence

What does "the spaces of 77,438 words" mean?

An Italian doctor named Paolo Mantegazza promoted the
medicinal and recreational use of the leaves of the coca plant in
the mid-nineteenth century. He was so enthralled by his discovery
that he wrote: “I sneered at the poor mortals condemned to live in
this valley of tears while I, carried on the wings of two leaves of
coca, went flying through the spaces of 77,438 words, each more
splendid than the one before . . .”