SLEEP 183 



highly improbable. Still, the conception has a symbolic 

 if not a literal value. We have seen in our general discus- 

 sion of fatigue that the synapses may be regarded as links 

 of low endurance, and this makes it reasonable to give them 

 a place in our hypotheses of sleep. 



It is curious to find that the idea that the junctions of 

 the neurons may, in some sense, open and close has been 

 used in two lines of speculation of a distinctly contrasted 

 character. According to the more familiar view already 

 outlined it is the breaking apart of the nervous units 

 which paralyzes objective and subjective activity. An- 

 other theory, originating in Italy and not widely known 

 here, makes precisely the contrary assumption,, that sleep 

 is the accompaniment of an extensive commingling of 

 cell processes. The establishment of new connections 

 between the neurons might explain the confusion and 

 irrational combinations occurring in dreams. The general 

 failure of reactions and, finally, of consciousness itself 

 might be explained as due to a dissipation of the nerve- 

 currents in so many paths that there should nowhere be 

 any effective intensity. Waking, then, might be pictured 

 as the resumption of intercourse among the neurons, or as 

 the restriction of intercourse to the usual serviceable chan- 

 nels after a period of disorderly diffusion. 



A mill is usually stopped by closing the gates and inter- 

 rupting the stream that has been turning its wheels, but 

 it could be stopped by opening sluices in the dam and 

 diverting a large share of the water. The two possi- 

 bilities correspond roughly with the neuron theories of 

 sleep. Either a cessation or a scattering of impulses within 

 the brain may conceivably result in unconsciousness. 

 The second theory is better adapted to an explanation of 

 dreams, a matter to which we must now turn. 



