Brain PuysioLocy or Worms 8359 
experiments had led me to suspect that this “spontaneous” 
or “instinctive” burial was only a reflex called forth through 
the stimulus of contact with sand. I tried whether it would 
not be possible under certain conditions to demonstrate the 
same reflex, even in brainless pieces. I laid such a brainless 
piece upon the sand; as usual it remained quiet. I now 
carefully covered the anterior end of this piece with sand. 
The rest of the animal soon began to execute the typical 
movements which are necessary to bring about the burial of 
the animal in the sand. At the same time the glands at the 
foot end of the animal began to secrete the sticky substance 
which cements together the grains of sand and renders solid 
the wall of the tube in which the animal lives. This secre- 
tion is a constant accompaniment of the burrowing of the 
animal. It isthe same secretion which in other worms leads to 
the formation of atube. The animal did not however succeed 
in burying itself, and so it soon began its movements anew. 
Spontaneous progressive movements were executed only 
by that piece which contained the brain. Yet weak stimuli, 
such as the shaking of the aquarium in passing through the 
room, sufficed to bring about progressive movements in the 
posterior piece. None of the pieces would remain on their 
backs when turned over. When I attempted to keep a 
brainless piece forcibly in this position it made great attempts 
to return to the ventral position. In all the experiments 
which have been described the size of the piece is not imma- 
terial: the more segments it contains the more definite are 
its reactions. I tried finally to determine whether all the 
ganglia even the most posterior are able to bring about the 
same winding and bending which is characteristic of the 
injured worm. That is indeed the case. 
VI. EXPERIMENTS ON LUMBRICUS FETIDUS 
I wished to determine whether angleworms are heliotropic 
or photokinetic, and whether the decapitated animals show 
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