XVIII 
THE MICROCOSM OF THE EGG 
ARWIN called the brain of the ant the 
most marvelous speck of matter in the 
universe. It is so intricate for its size—less than 
that of a pin’s-head; it is the repository of so 
many ready-made tricks. But even more marvelous 
than the ant’s brain is the much minuter ant’s egg- 
cell (what we buy as “ants’ eggs’’ are pup under- 
going metamorphosis), which, in a manner that we 
cannot begin to imagine, contains the potentiality 
of the whole insect and of all its instincts as well. 
The more we know about the ovum, the more the 
wonder grows. It may be of interest, then, to look 
for a little into the pit whence we were digged, 
and upon the rock whence we were hewn. For, 
like most other living creatures, we all begin as 
fertilized egg-cells. A convenient up-to-date ac- 
count of the whole matter will be found in Professor 
Brachet’s L’CEuf (1917), a brilliant course of lec- 
tures which this embryologist of Brussels has re- 
cently delivered at the College de France. 
The egg-cell, or ovum, is typically a very minute 
living unit. The dark-colored ovum of the frog 
is about one-tenth of an inch in diameter, but this 
is gigantic compared with the ovum of most 
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