3846 STUDIES IN GENERAL PHYSIOLOGY 
has the further advantage of being satisfied by a single experiment, 
in so far as, of the two elements of which the definition is com- 
posed, the one element is always given anatomically. This is the 
higher sensory nerve, the presence of which guarantees its func- 
tion. The only experiment which it is necessary to perform has to 
prove that the general center of locomotion is also present beside 
the sensory apparatus. This proof is furnished when the unilateral 
removal of the central nervous portion’in question so alters the 
direction of the movement of the animal that it no longer moves 
in a straight line but in a circle—a phenomenon which is generally 
designated by the term “forced movements.” 
This definition of Steiner leads to two new conclusions: 
first, that the cerebrum in human beings does not belong to 
the brain since, as is well known, unilateral removal does 
not bring about forced movements. Steiner himself realizes 
this, for he has found, aided by his definition, that the octo- 
pus “has a cerebrum but no brain.” ‘To have no brain 
and yet a cerebrum seems strange and even paradoxical, 
probably only, however, because we have not until now encoun- 
tered such a case.” The second necessary conclusion from 
Steiner’s definition is that the ear isa brain. This conclu- 
sion has not been drawn by Steiner himself, but is unavoid- 
able. For, first, unilateral extirpation of the ear brings 
about forced movements, and, secondly, the auditory nerve 
is one of the higher sensory nerves. Steiner further points 
out that bilateral destruction of an organ, the unilateral 
destruction of which brings about circus motions, renders 
impossible spontaneous progressive movements. Forced 
movements can be brought about in the shark from the 
medulla oblongata, and here is located also, according to 
Steiner, “the general center of locomotion” of this animal. 
Steiner has himself shown, however, that a shark still moves 
spontaneously after the loss of the entire medulla oblongata! 
This “center of locomotion” is said by Steiner to be 
located in the medulla oblongata in the frog also, but 
ISTEINER, Die F'unctionen des Centralnervensystems, Vol. II (1883), pp. 56 ff. 
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