CENTRAL NERVOUS SYSTEM. 263 



From the experimental work of the strict localizationists like Hitzig, 1 

 Munk, 2 and Ferrier, 3 and from the work of those who, like Goltz 4 and Loci)/' 

 denied a strict localization in the cerebral cortex, several important points 

 of view have been developed. 



In the first instance, anatomy indicates that in the central system there- 

 are but few localities which consist only of one set of cell-bodies, together 

 with the fibres coming to these bodies and going from them. Almost every 

 part has both more than one set of connections with other parts and also 

 fibres passing through it, or by way of it, to other localities. Hence in re- 

 moving any part of the hemispheres, for instance, not only are groups of cell- 

 bodies taken away, but a number of other pathways are interrupted at the 

 same time, and thus the damage extends beyond the limits of the part re- 

 moved. Moreover, when any portion of the central system has been removed 

 there is a greater or less amount of disturbance of function following imme- 

 diately after the operation ; but this disturbance partially passes away. 

 There are thus "temporary" as contrasted with "permanent" effects of the 

 lesion, and these require to be sharply distinguished, because it is a per- 

 manent loss which is alone significant in these experiments. Finally, it has 

 been made clear that neither the relative nor the absolute value of any 

 division of the central system is fixed, but depends on the degree to which 

 centralization has progressed, or, to use the more common measure, the grade 

 of the animal in the zoological series, both expressions implying an increase 

 in the connections between the cerebrum and the lower centres. The age of 

 the animal on which the operation has been made is also of no small impor- 

 tance in this respect. These relations can be illustrated by reference to several 

 experiments. 



Removal of Cerebral Hemispheres. — If from a bony fish the cerebral 

 hemispheres (including the corpora striata as well as the mantle) be removed, 

 the animal apparently suffers little inconvenience. The movements are un- 

 disturbed ; such fish play together in the usual manner, discriminate between 

 a worm and a bit of string, and among a series of colored wafers to which 

 they rise always select the red ones first. 6 In these fish the eye is the con- 

 trolling sense-organ, ami, as will be recognized (see Fig. 114), the operation 

 has by no means damaged the primary centres of vision. 



Quite different is the result when the cerebrum is removed from :i shark.' 

 In this case, although the eyes are intact, the animal is reduced to complete 

 quiescence; yet, on the whole, the nervous system of the shark is rather less 

 well organized and more simple than that of the bony fish. 



The astonishing effect produced is explained by a second experiment (see 

 Fig. 115). 



1 Untersuehungen ueber daa Oehirn, Berlin, 1874. 



2 Ueber die Funettonen der Orosshimrinde, Berlin, 1881. 



3 The Functions i if tin- llrdhi. London, 1S7(>. 



* Ueber die Veriehtungen dea Gfrosshirns, Bonn, 1881. 



8 Archiv fur die gesnmmte Physiologic, 1884, Bde. 33 a. 34. 



6 Steiner : Die Functional der Centralnervensystems, 1888. 'Steiner: Loe. cit. 



