LECTURE XI. 



much smaller, namely, the grey, or ganglionic, substance, 

 has hitherto opposed difficulties even to histological in- 

 vestigation which are still far from being overcome, so 

 that the experimental examination of this substance has 

 scarcely been able to be taken in hand. It is indeed 

 often maintained that a great deal is now known about 

 the nervous system, but our knowledge is for the most 

 part confined to the white substance, the fibrous portion, 

 whilst we are unfortunately obliged to confess that, both 

 in an anatomical, but more especially in a physiological 

 point of view, we are still involved in the greatest uncer- 

 tainties with regard to the grey substance, which, as far 

 as its functions are concerned, manifestly holds a much 

 higher position. 



As soon as we consider the question of the influence 

 exercised by the nervous system in the different pro- 

 cesses 'of life, anatomically, a single glance suffices to show, 

 that the point of view which neuro-pathologists have 

 been accustomed to set out with, is a very erroneous one. 

 For they fancied they saw in the nervous system an un- 

 usually simple whole, from the unity of which resulted 

 the unity of the body in general, of the whole organism. 

 But even though one has nothing but very rough anato- 

 mical ideas concerning the nerves, still one ought not to 

 shut one's eyes to the fact that this unity is in a very 

 sorry plight, and that even the scalpel demonstrates the 

 nervous system to be an apparatus composed of an ex- 

 tremely large number of parts of relatively equal value 

 without any single discoverable central point. The more 

 accurately we make our histological investigations, the 

 more do the elements multiply, and the ultimate compo- 

 sition of the nervous system proves to be disposed upon 

 a plan analogous to that which has been followed in all 

 the other parts of the body. An infinite quantity of 

 cellular elements manifest themselves side by side, more 



