HYPNOTISM AND ITS PHENOMENA. 65 
sleep founded on one isolated though comprehensive fact. Dr. Cappie’s 
theory is one which seems to comprise many more of the factors enter- 
ing into the causation of sleep. Briefly, he says: (1) there is with the 
growing exhaustion, towards evening, of all the tissues a lessened 
molecular activity of the cerebral cells, and (2) coincidently there- 
with a change in the capillary circulation of the brain so that less 
blood is supplied to the brain, and hence the volume of the brain is 
less. But (3) this situated within the immobile capsule of the 
cranium must have the hitherto occupied space, now again filled ; 
hence, as Arthur Durham remarks, the result is that the blood in 
the venous sinuses is increased. But further, Mr. J. Hilton, F.R.C.S., 
remarks that the cerebro-spinal arachnoid fluid always equipoises the 
haemic condition of the brain, and especially of the parts surround- 
ing the ventricles—thus resting the brain; and not only so, but 
also the relation between this fluid and the blood is always one of 
unstable equilibrium. But, once more, Dr. Hughlings Jackson has 
shown that the ophthalmoscopic disc is in sleep always in an anaemic 
condition. Now all this seems simple enough, yet I doubt not that 
many abnormal states may arise which will be found difficult to co- 
apt with thistheory. However, this theory would further seem to 
be supported by what we find present in many pathological condi- 
tions. Thus we know that in active delirium, dependent upon an 
hyperaemia and inflammation of the brain, sleeplessness is a common 
symptom, ¢. g., acute mania and the early stages of acute meningitis, 
while again in the later stages of both there is unconsciousness and 
more or less complete coma arising from venous stasis and effusion of 
lymph into the cerebral tissues. This in an organ with such an enor- 
mous capillary circulation—the encephalon containing, according to 
Haller, § of the total blood of the body—must produce the most dis- 
astrous effects upon its functional activity as has been experimentally 
shown in many ways. Thus pressure upon a portion of brain exposed 
by a fractured cranium has immediately produced a suspension of its 
functional activity, thereby inducing unconsciousness. That it is 
anaemia which has produced this state is evident from the fact that 
a removal of the pressure brings back immediately functional activity 
of the part. 
Before we endeavour to draw a parallel between the physical con- 
ditions of natural sleep and induced hypnotism, we shall try and ex- 
plain how the anaemia of natural sleep is produced. 
5 
