1898] RUDIMENTARY NERVOUS SYSTEM 387 
ments need to be performed in a dark room, or at night, by illuminat- 
ing the liquid with the somewhat oblique rays of a candle so as to 
obtain a marked shadow. Fill a floating dish with water and pour 
on its surface a small quantity of petroleum. (Fig. 21.) This forms 
large drops, on the edges of which appear certain pseudopodia with 
terminal spheres: these advance inwards originating therein several 
curious phenomena which are of no consequence at present. 
The drops of petroleum playing the part of the neuroplasma or 
that of the nervous elements in evolution, project a distinct shadow 
on the white ground of the dish. Water is the actor intrusted with 
the all-important part of the neuroglia. 
Some other liquids may likewise serve the purpose, since there 
is nothing indispensable, except the question of their densities and 
the indissolubility of the one in the other. 
In fig. 21 there are five large masses of neuroplasm scarcely 
differing from each other (young foetus). But when any waves are 
produced in a single direction (acoustic impressions for instance) A 
and B are divided (fig. 22) and six different elements result from 
this mechanical division. Then, whenever the vibration continues 
with increasing intensity, one of the drops lengthens, adhering by 
one of its sides to the neuroglia or water, and finally constituting 
a kind of myelocyte, undergoes tension in several directions and 
sends the element ¢ forth. We now have eight drops instead of 
the five primordial ones and a very small one, a little like the 
nervous embryonic cells (fig. 23). Still the experimenter goes on 
his task of differentiation and provokes many waves in two directions, 
obtaining thirty-seven more or less deformed drops (fig. 24). To 
close the experiment a new undulatory motion is provoked with a 
thick pin in a single direction and some currents of bipolar, multi- 
polar, apolar, and articulated cells are formed, some resembling 
neuromata, while others are elliptical and have nuclei in them. 
(Fig. 24.) Though these figures are transitory I believe that per- 
manent ones could be obtained by employing a melted grease which 
would preserve the shapes acquired by vibration as it cooled. The 
vibration can be provoked either in the water or in the floating 
drops of petroleum themselves. 
Conclusions.—The origin of individuals and the construction of 
the organism by internal conditions is an exceedingly probable 
principle ; even the origin and functions of the nervous system may 
generally be explained by vibrations, by waves running through 
certain conductors of neuroplasma and modifying it mechanically 
with regard to its shape, division, and connections. Every cause 
influencing general nutrition will modify the physical and chemical 
properties of the neuroplasma and of the neuroglia in whose bosom 
it slowly performs its boundless evolution. 
