PLANT AND ANIMAL LIFE. 
CHAPTEE XXII. 
THE UNIVERSE OF LITTLE THINGS. 
As soon as man discovered the principle of the 
refraction of light he opened new possibilities for 
himself. This principle he applied to the construc¬ 
tion of the telescope and the spectroscope, instruments 
which have brought to him new visions and new 
knowledge from the immensities of space. Great 
spheres moving at great velocities in great orbits come 
within range of his scrutinizing gaze. But even while 
he was pondering upon the great and the far distant, 
there lay at his feet another world quite as wonder¬ 
ful, into which the microscope was soon to lead him. 
Though the microscope was invented soon after 
the telescope, men were slow to see with it. It was 
not much over a quarter of a century ago that it was 
turned to practical uses. The discoveries made in 
this time, and particularly in the last ten years, have 
introduced man into a new universe—the universe of 
little things. 
Let us get some idea of this world. We will begin 
by taking a little yeast from the sponge of mother’s 
bread and place it on the slide of a good microscope. 
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