CONSCIOUSNESS. 73 



For in our own organisms we know that reflex actions arc 

 not accompanied by consciousness, although the complexity 

 of the neuro-muscular systems concerned in these actions 

 may be very considerable. Clearly, therefore, it is not meie 

 complexity of ganglionic action that determines conscious- 

 ness. What, then, is the difference between the mode of 

 operation of the cerebral hemispheres and that of the lower 

 ganglia, which may be taken to correspond with the great 

 subjective distinction between the consciousness which may 

 attend the former and the no-consciousness which is inva- 

 riably characteristic of the latter ? I think the only difference 

 that can be pointed to is a difference of rate or time. We 

 know by actual measurement, as we shall subsequently see 

 in more detail, that the cerebral hemispheres work more 

 slowly while undergoing those changes which are accom- 

 panied by consciousness than is the case with the activities 

 of the lower centres. In other words, the period between the 

 fall of a stimulus and the occurrence of responsive movement 

 is notably longer if the stimulus has first to be perceived, than 

 it is if no perception is required. And this is proved, not 

 only by comparing the latent period (or the time which 

 elapses between the stimulation and the response) in the case 

 of an action involving one of the lower centres and that of an 

 action involving the cerebral hemispheres in perception ; but 

 also by comparing the latent period in the case of one and 

 the same cerebral action which from having originally involved 

 perception has through repetition become automatic. An old 

 sportsman will have his gun to the shoulder, by an almost 

 unconscious act, the moment that a bird unexpectedly rises; 

 a novice similarly surprised will spend a valuable second in 

 " taking in " the situation. And any number of similar facts 

 might be given to show that it* few things are "as quick as 

 thought," reflex or automatic art inn is one that is quicker. 

 Further, in a general way it can be shown that the more 

 elaborates Btate of consciousness is, the more time is required 

 for ite elaboration, as we shall see more in detail when we 

 come t<> treat <>t' Perception. 



Now whal does this greater consumption of time imply? 

 It clearly implies that the nervous mechanism concerned has 

 not been fully habituated to the performance of the response 

 required, and therefore thai instead of the stimulus merely 

 needing t<> touch the trigger of a ready-formed apparatus of 



