THE MICROCOSM OF THE EGG = 139 
said, as .the weaver at the loom, the paternal and 
maternal contributions being the warp and woof 
of the future web. (4) When the sperm-cell enters, 
a wave of contraction, starting from the upper pole, 
passes through the ovum, and a small quantitiy of 
fluid is expelled which insinuates itself between the 
surface of the egg and the innermost layer of the 
egg-membranes. ( 5) Finally, the sperm-cell sets up 
awakening changes in the living substance of the 
egg, which then passes from static to dynamic 
equilibrium. The formative materials are redis- 
tributed and stabilized in a direction determined by 
the meridian of the sperm’s entrance. This new 
architecture is respected in the subsequent cleavage 
of the developing egg. Another effect is that the 
living substance of the ovum becomes suddenly 
refractory to the entrance of another sperm-cell, 
which would be apt to induce monstrosity. This 
“blocking” of the egg-cell is sometimes accom- 
plished by the contraction, already referred to, 
which shuts a little gateway (micropyle) present in 
the egg-envelope of many ova, 
One of the most interesting chapters in modern 
biology concerns artificial parthenogenesis, i.e. 
experimental ways of launching an unfertilized egg 
on the voyage of development. Most bee-experts 
believe that unfertilized eggs laid by the queen 
develop into drones, who, therefore, have a mother 
but no father. This is natural parthenogenesis, 
and there are many other instances. But it is now 
known that in a variety of cases, from sea-urchin to 
