140 PHYSIOLOGY. 



between its several parts, and therefore does not admit of re- 

 covering the several relations which are necessary to determine 

 the identity or presence of any object. 



" 2. False judgments with regard to things really existing. 

 Although most of these probably arise from the state of the 

 organ (compare p. 52.), we consider them as depending upon 

 the brain, when there is a want of steadiness in viewing objects, 

 making us hesitate about their reality, which is owing to a 

 considerable debility of the brain ; or when, on the contrary, we 

 see more vivid colours ; as when in fevers the eyes throw a red 

 colour over every object, or when a well known figure appears 

 distorted, &c. ; also when the powers of reminiscence and me- 

 mory have been impaired by causes operating upon the brain, 

 in consequence of which persons feel a want of several circum- 

 stances necessary to ascertain the identity of the objects, and to 

 give the proper complex idea (LXII.). 



" 3. Of the unusual quality of impressions (comp. p. 53.) it 

 is difficult to say when it depends on the sentient extremities, 

 and when on the brain. We may, however, take this as a 

 means of judging. Where it is a pure and single idiosyncracy, 

 affecting one person and one part of the body, we believe that it 

 depends on a certain modification of the sentient extremities of 

 the part ; but where it is connected with the whole tempera- 

 ment, with a certain disease, or is the immediate consequence of 

 a disease, I should suspect a peculiar state of the brain ; as 

 when to a hysteric woman a rose is disagreeable, and asafcetida 

 particularly agreeable ; and when this change of the agreeable 

 and disagreeable, for instance, takes places constantly in a cer- 

 tain temperament, 



"II. To consider how the same state of the brain affects mo^- 

 tion in the body, we shall, as before, treat of the states of vigour 

 and of mobility (LXXXIX.) ; and, 1. With regard to the state 

 of vigour and debility, (comp. p. 93.) I have endeavoured to 

 prove that there is not a muscular fibre in the system, which 

 -does not for its power depend upon the sufficient vigour of the 

 energy of the brain, and that without it the muscular actions 

 are much more languid and weak. Now the vigour of the 

 brain depends upon the state of the original conformation, or, 

 according to the language which we use, upon the original sta- 



