DEDIFFERENTIATION IN PEROPHORA 685 
We shall now see that similar relations may exist in non- 
conscious neural processes, of which the lower have never 
been fully dominant in ontogeny (though possibly in phylogeny). 
This is well shown by the observations of Head and Riddoch 
(1917) on the activities of ‘spinal man’. They found that when 
the spinal cord was completely divided, the reflex activities 
which manifested themselves after the initial shock-period 
were very different from those occurring in the uninjured 
individual. In the normal person the activities of the spinal 
cord are modified by influences reaching it from pre-spinal 
levels. The isolated spinal cord, however, responds to stimula- 
tion predominantly by a type of ‘ mass-reflex’ not normally 
seenin man. In‘ spinal man’ any form of nocuous stimulation 
to a hind-limb causes not merely flexion of the limb stimulated, 
but violent flexion of both limbs, abdominal contraction, 
voiding of the contents of the bladder if the contained fluid 
is above a certain very small volume, and sweating. Con- 
versely, injection of the bladder with fluid induces a flexor 
spasm of the lower limbs, combined with sweating. (The 
reaction may be called an excessive and non-discriminate 
reaction to harmful stimuli, resembling in many ways that 
seen in certain lower animals, e.g. the toad, in which voiding 
of the bladder accompanies limb-flexion when the animal is 
alarmed by handling.) The same mass-reflex also appears in 
higher forms and in man himself when the higher centres are 
put out of action under the influence of an excessive degree of 
an emotion such as fear (differential inhibition). The mass- 
reflex may be looked on as a very primitive response of the 
organism to nocuous stimuli. 
In higher forms the mass-reflex has become subordinated to 
the influence of other types of reaction ; among these are the 
postural reactions and the conscious direction of movements 
of escape. Head and Riddoch found that so long as any 
and both adapted (though incompletely) to adult life. The emergence of 
the juvenile personality ‘Sally’ in Morton Prince’s case is especially 
interesting as it only occurred when the normal control was impaired 
through the dissociation of the adult personality into two. 
NO. 260 ZZ 
