Dragon-flies shoot in vigorous zigzags through the dancing swarms, and a rich profusion of butterflies--the leguminosae of insects--make a fine addition to the general show.

Many of these last are comparatively small at this elevation, and as yet almost unknown to science; but every now and then a familiar vanessa or papilio comes sailing past.

Humming-birds, too, are quite common here, and the robin is always found along the margin of the stream, or out in the shallowest portions of the sod, and sometimes the grouse and mountain quail, with their broods of precious fluffy chickens.

Swallows skim the grassy lake from end to end, fly-catchers come and go in fitful flights from the tops of dead spars, while woodpeckers swing across from side to side in graceful festoon curves,--birds, insects, and flowers all in their own way telling a deep summer joy.
The influences of pure nature seem to be so little known as yet, that it is generally supposed that complete pleasure of this kind, permeating one's very flesh and bones, unfits the student for scientific pursuits in which cool judgment and observation are required.

But the effect is just the opposite.