446 PROGRESS OF SCIENCE IN THE CENTURY. 



specialised centres both sensory and motor. And to 

 this experimental investigation there has come aid 

 from histological studies, especially since the refine- 

 ment of methods due to Golgi and Ramon y Cajal. 



Although a splendid beginning has been made, 

 it is only a beginning, and even among experts there 

 is much diversity of opinion on important questions. 

 Thus we find Flechsig mapping out three levels 

 of centres in the cortex, sense-centres (also motor), 

 association-centres (with indirect motor connections), 

 and between these in order of development inter- 

 mediate centres; while, on the other hand, we find 

 Loeb * maintaining that while there exists to a cer- 

 tain extent an anatomical localisation in the cortex, 

 the assumption of a physical localisation is contra- 

 dicted by the facts ..." In processes of associa- 

 tion the cerebral hemispheres act as a whole, and not 

 as a mosaic of a number of independent parts. . . . 

 It is just as anthropomorphic to invent special centres 

 of association as it is to invent special centres of co- 

 ordination." f 



Summary. — It must he admitted hy all that 

 '' there exist manifold correspondences of the most in- 

 timate and exact kind hetiveen states and changes of 

 consciousness on the one hand, and states and changes 

 of brain on the other. As respects complexity, in- 

 tensity, and time-order the concomitance is appar- 

 ently complete. Mind and brain advance and decline 

 pari passu; the stimulants and narcotics that en- 

 liven or depress the action of the one tell in like 

 manner upon the other. Local lesions that suspend 

 or destroy, more or less completely, the functions of 



♦Loeb Comparative Physiology of the Brain (1900), 

 p. 262. 

 t Loeb, p. 275. 



