252 ELEMENTS OF SCIENCE 



through observations on injured men, the best evidence 

 of the existence in them of " reflex action." A man 

 whose spinal cord has been greatly injured loses all 

 power of both sensation and voluntary motion in those 

 parts of the body supplied by nerves which come forth 

 from the spinal cord below the place of injury. At 

 the same time movements of those very parts (often 

 exaggerated movements) may be produced by pinching, 

 burning or tickling such parts, without the patient 

 having any corresponding feelings, or any conscious- 

 ness of the movements which he may see, that his own 

 limbs are thus made to perform. 



But while the nervous system of man ministers to all 

 those feelings, single and associated, which result in 

 such sense-perceptions and " consentience* " as the cat 

 possesses, it also ministers to much higher powers 

 than those which any beasts possess. We can describe 

 a beast, but no beast can describe a man. The most 

 important difference, then, between man and all the 

 other objects of nature we have yet considered, is the 

 difference which exists between his power of conscious 

 thought, his intellectuality, and all the powers possessed 

 by any other creature of which our senses can give us 

 cognisance. 



The study of this intellectual power and of the lower 

 power of mere feeling, sense-perception, &c., which 

 accompany it, constitutes a distinct study, which is 

 usually designated Psychology. This study not only 

 differs greatly from all other studies, as regards the 

 object to which it is directed, but it differs absolutely 

 from them as to the mode in which alone it can be 

 carried on. In every other study our attention is 



* See ante, p. 227. 



