Meyer, Data of Modcjii Neurology. 145 



columns of the spinal cord, the fibers from the segments of the 

 lower extremity next to the median line, those from the brach- 

 ial segment to their side, and finally those of the head yet fur- 

 ther to the side as is seen from the drawings of the cord and 

 medulla oblongata. 



After an interruption and sifting in the optic thalamus, 

 secondary afferent elements meet in the cortex the cerebral effer- 

 ent neurones which form the pyramidal tract, the so called 

 voluntary motor path, and their equivalents within the optic, 

 auditory, etc., region. The forebrain is an exceedingly com- 

 plicated mechanism ; as one would expect from the tremendous 

 complication of all the conscious activity of which we are capa- 

 ble, its differenciation apparatus is very elaborate. 



There remains to be mentioned, that the higher mechan- 

 isms, cerebellum, midbrain and forebrain have connections 

 among one another, not drawn in the chart (Fig. 6) in order not 

 to complicate the drawing. Further we must say that this pre- 

 liminary sketch of three supersegmental apparatus will require 

 subdivisions and perhaps even additions in number. They are 

 units only in the most general way, and given here as the types 

 now most important. 



This outline will, I hope, make clear the general point of 

 view. It can perhaps be more forcibly Illustrated in the follow- 

 ing manner : 



We saw that Forel formulates the laws of v. Gudden's de- 

 generation experiments as follows : if a cell body is removed, 

 the fiber belonging to it will degenerate, if a fiber termination 

 in the central nervous system is cut, where regeneration is im- 

 possible the whole cell will atrophy slowly, and, in the case 

 of the new-born at least, degenerate and disappear. 



In accordance with the fundamental laws of the pathology 

 of the central nervous system, we would therefore formulate 

 our general point of view in this manner : 



The phylogenetically oldest mechanisms are the sensory- 

 motor apparatus constituting the purely segmental nervous sys- 

 tem as defined above. Over them, lifted out from them for 

 topographical centralization, there are specialized mechanisms, 



