70 Indications of a Central Zone of Development 
general law of organic development, are phenomena 
which indicate in their turn that this centroepigenesis 
with ramifying, independent networks for the distribu- 
tion of nervous energy, is also in harmony with the most 
general biologic phenomena. 
One could always bring forward the objection that it 
is difficult to conceive how this series of energies acting 
one after the other, all upon the same point of the de- 
veloping organism, could give rise to a series of dynamic 
systems of distributions as complex as we must neces- 
sarily suppose those to be which constitute the successive 
stages of ontogeny. To dissipate all doubts in this mat- 
ter one may draw attention to the following simple 
hydro-dynamic experiment. 
Let us imagine a very large cylindrical glass container 
almost filled with water, and having a hole at a selected 
point in the bottom of it. By means of a suitable force 
pump let us make more water enter the vessel through 
this hole with a velocity varying from one moment to 
another. To make the idea clear and the phenomenon 
more intelligible let us suppose that the velocity varies 
sharply each second, sometimes increasing, sometimes 
diminishing very considerably. On account of the great 
amount of water already contained in the vessel, the 
series of successive systems of very complex: currents 
which will be produced each moment by the incoming 
water, whose newly added mass interpenetrates and dis- 
places the other in a manner which we can make appar- 
ent in part by previously coloring the water to be injected, 
will depend on the entire series, and exclusively on the 
series, of different velocities with which the water is 
forced into the container. 
A given series of dynamic actions, qualitatively alike 
