290 STUDIES IX LIFE AND SENSE. 



" consciousness " or thought of the danger which threatened our 

 person. 



Now, all of these actions took place so quickly that their accu- 

 rate analysis might well seem to be impossible. Still, the se- 

 quence of events proves the accuracy of the statement that the 

 seat of knowledge, and in this case the power of acting or walking 

 by sight, is resident in some part of the brain, to which it is the 

 function of the eye and optic nerve together to convey the impres- 

 sions and sensations on which our knowledge depends. But the 

 effects of the threatened blow erjd not thus with the declaration of 

 " information received " emanating from the brain. Like an active 

 and efficient official, the brain is prone to act upon such intelligence. 

 The head is withdrawn from the blow, the body itself is removed, it 

 may be some paces backward ; and unless discretion be deemed the 

 better moiety of valour, there may be responsive and co-ordinated 

 muscular actions of hands, arms, and possibly of legs or feet as well, 

 wherewith swift and sure retaliation may be made upon the sensi- 

 ferous organs and most tangent regions of our antagonist. In other 

 words, if an impression has been received by the brain, it is no less 

 plain that another or it may be several impressions have issued 

 from the seat of mind. 'These have radiated, as directed by the 

 brain, to the muscles of our head and neck, and to those of our 

 limbs ; and our subsequent movements are the result of this secon- 

 dary brain-act which follows upon the reception of the previous 

 impression. Thus we begin to understand that, in their nature, 

 ordinary nervous acts are really double, and that all our ordinary acts 

 and our extraordinary actions as well are regulated by a kind of duplex 

 telegraphy on the part of the nervous system. It also becomes 

 apparent that even the confused heat and bustle of a severe scrim- 

 mage or the whirling maze of heads, hats, and coat-tails which are 

 popularly believed to constitute an enlivening feature of festivals of 

 which Donnybrook remains the type may, through a patient scien- 

 tific enquiry, be resolved into so many sensations received and acted 

 upon through the system of mind-telegraphy just described. 



It remains, therefore, a plain doctrine of modern physiology that 

 our knowledge of the outer world is received and acted upon through 

 a very definite system of actions and reactions. True, we do not 

 know what constitutes an impression. We have measured the rate 

 at which nerve-force travels, but the exact nature of this force is 

 unknown. Consciousness and the reception of impressions by the 

 brain has not advanced materially in explanation since Hartley, in 

 his "Observations on Man," spoke of the "vibrations of the small, 

 and, as we may say, infinitesimal medullary particles," which he con- 

 ceived further to be " motions backwards and forwards of the small 

 particles " of the brain, and to present a similarity to " the oscilla- 



