SENSE AREAS AND ASSOCIATION AREAS. 



203 



observed that the most positive and invariable symptom of lesions 

 in this region is a condition of astereognosis, that is, a diminution 

 in what may be called the stereognostic perceptions.* By stereog- 

 nostic perception is meant the power to judge concerning the form 

 and consistency of external objects when handled, and it must be 

 regarded as a perception based upon localized sensations of touch, 



Centred Sulcus 



-Internal arcuate pbe 



Qjblnal Cord- 



Fig. 90. — Schema representing the origin and course of the fibers of the median fillet, — the 

 intercentral paths of the fibers of body sen.>5e. 



together perhaps with those of temperature and muscular sen- 

 sibility. On the whole, therefore, we must infer that the cortex in 

 this postcentral area is concerned with the sensations of pressure, 

 temperature, and muscular conditions, and especially the higher 

 type of these sensations, which we can project or localize accurately. 

 This conclusion is strengthened by the fact that, as described in 

 the next paragraph, the fibers of the lemniscus terminate in this 

 same region. Secondly, in this region there are mediated also 

 * Frazier and Ingham, "Trans. American Neurological Association," 1919. 



