CHAPTER XVII 
THE BIRD IN THE EGG 
HE embryology, or life of the bird in the egg, is 
the most mysterious and wonderful part of the 
22s} entire physical aspect. Many of the lesser de- 
‘ail of growth are very difficult to study without the 
use of microscopic sections and wax models; but a little 
knowledge of the subject is more interesting and simple 
than one would imagine. 
The very best way to begin our study of the life in the 
egg will be to go to the nearest pond or marsh, if it is spring- 
time, and bring home a pailful of freshly laid frog’s eggs 
—those queer, gelatinous masses filled with black dots. 
Place them in a flat, white basin, and into a smaller saucer 
near by break a fresh hen’s egg, being careful not to injure 
the yolk. Separate one of the frog’s eggs with a spoon 
and put it beside that of the fowl. Now examine them 
carefully with a good dissecting-microscope or even with 
a hand-lens. 
We see a large, round, yellow yolk in the case of one 
egg, and a tiny speck of black and white in the other,— 
both apparently inanimate bits of matter, but which, 
merely by the application of heat in the one instance 
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