OF MYRIAPODA AND MACROUROUS ARACHNIDA. 
•269 
results were precisely similar to those of experiments 6 and 7, and the movements 
were to the right, the side injured in this specimen. 
Experiment 9. — The right eye and optic ganglion were both destroyed by punctur- 
ing with a fine needle. The antenna of that side of the head became completely 
motionless, and perception of objects was destroyed ; but the animal still retained its 
voluntary powers, and was able to recognise objects on the left side, on which the 
antenna and eye were uninjured, and seemed to a great degree to retain their usual 
powers. 
Experiment 10. — Both antennae were cut off close to the head, leaving the brain 
uninjured. All the powers of the animal continued perfectly voluntary, and it sought 
or avoided objects as usual, but by means of the palpi and vision, with not the 
slightest indication of reflex movements. When the point of a needle was passed in 
at the antennae, the animal gave indications of great pain by its movements, but these 
were not reflex. When placed on the table it again sought objects, and carefully 
avoided falling over, by changing its course when it arrived at the edge. The brain 
was then destroyed through the insertion of the antennae, and the movements imme- 
diately became reflex, and soon ceased, except when they were artificially re-excited. 
Experiment 11. — The eyes on both sides of the head were removed without in- 
juring the brain or antennae. Volition continued perfect, but the movements of the 
animal were slower, and all objects were very carefully explored with the antennae ; and 
it avoided nothing except when in direct contact with it, or when its presence had been 
ascertained by means of these organs. But immediately the needle was passed into 
the brain all the motions became reflex and precisely similar to those already de- 
tailed. 
These experiments on lulus sufficiently prove that the seat of sensation and voli- 
tion is in the cerebral ganglia, and that when these are destroyed, or greatly injured, 
all consciousness ceases and the movements of the body are reflex, and not voluntary. 
But it seemed necessary to confirm these conclusions by similar experiments in a 
higher form of Myriapoda, in which, from the peculiar structure of the head, the 
cerebral ganglia could be removed from the body without removing the medulla 
oblongata, from which the nerves are given to the parts of the mouth ; and further, 
that the experiments should be made on an animal in which the ganglia of the cord 
are large and quite distinct, and are removed from each other, and thus afford a 
better comparison with experiments made on the large Crustacea, in which the ex- 
periments on the brain cannot be so satisfactorily performed. The subject selected 
for this purpose was Lithobius forjicatus. 
Experiment 12. — The front of the head and the brain were removed at once by the 
scissors. All volition instantly ceased, and reflex movements were induced. The 
mandibles were in constant action as in manducation, and the body performed on- 
ward progressive movements, which gradually ceased, as in lulus, but there were 
no attempts to escape. When placed on its back the body instantly regained its 
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