298. EMBRYOLOGY AND CLASSIFICATION. 
of his arteries may not disturb the steadiness 
of his gaze, and the condition of his nervous 
‘system be so calm that his whole figure will re- 
main for hours in rigid obedience to his fixed 
and concentrated gaze. 
After these remarks IJ trust I shall not be mis- 
understood by those who have been working in 
the field of microscopic investigation, and for 
whose persevering devotion no one can ‘feel a 
deeper reverence than I do, if I add that there 
is as yet hardly a beginning in the study of the 
egg during-its growth, and anterior to the for- 
mation of the germ. Since Embryology became 
a science, the great aim of students in that de- 
partment has been to demonstrate the uniform 
structure of the egg in all animals, and investi- 
gators have limited their observations to that 
stage of the ovarian egg during which it ap- 
pears in all animals as a perfect cell. But a 
new field now opens before us, requiring a care- 
ful survey of every stage of growth of the egg, 
from its first formation to the period when a 
well-defined germ is developed. The growth of 
the egg during this period requires to be studied 
as minutely through all its changes, and in the 
various combinations of its constitutive elements, 
as the germ itself has been in its later trans- 
formations. Here again, in this later phase, 
another field presents itself equally new and 
