616 LECTURE XXVI. 



nerve-tissue. We observe all sorts of different symptoms, one of the most 

 characteristic being the readiness with which the patient becomes fatigued. 

 One gets the impression that the nerve-centers have but a limited supply 

 of material at hand, or that the combustible material is consumed rapidly 

 without a sufficient regulation. This, however, is merely supposition 

 and rests upon no foundation. In the case of organic nervous diseases, 

 the symptoms of which are characteristic according to the nerves and 

 nerve-centers that are affected, we find degeneration. The nerve-cells 

 and their processes are destroyed. We may say that the experiment 

 has been tried, to trace some relation between the selection which certain 

 poisons, e.g. lead and " syphilis poison," show toward the various nerve- 

 paths and the activity of the metabolic processes in special regions. 

 Those nerve-paths and nerve-centers are assumed to show soonest the 

 action of the poison which are most affected because they have the most 

 work to do. As interesting as this hypothesis of Edinger * may be, we 

 must state that there is absolutely no direct proof possible at present. 

 As long as the physiological course of metabolism remains so obscure, it 

 is very difficult indeed for us to get any clear idea from pathological 

 deviations. We can, it is true, imagine that cells which are in constant 

 activity and are constantly being used up and reconstructed, will feel the 

 effects of a given poison much more rapidly than those which are fairly 

 stable. This, however, does not necessarily imply that there is an exhaus- 

 tion in the sense meant by Edinger, but rather it may be that there is an 

 effect upon the more active supply of new material and increased con- 

 sumption which is necessary for the exercise of the enlarged function. 

 We know that there are certain cells, e.g., of infusoria, algae, etc., which 

 have a particular power of attracting certain metals, even when the latter 

 are present in extremely slight amount. They take up these substances 

 even from very dilute solutions and store them up. This may very easily 

 cause the destruction of the cells, evidently in part, at least, on account of 

 the fact that these substances combine with the constituents of the cell 

 in such a way that they prevent the further exercise of function by the 

 cell-protoplasm, and to some extent destroy the cell. Similarly it is 

 conceivable that the interposition of the above-mentioned poisons between 

 the separate constituents of the protoplasm of nerve-centers, disturbs the 

 normal construction of the cells, and, therefore, its functions. There is 

 not necessarily any affinity existing between the nerve-cell as a whole, 

 and the poison in question, for it is perfectly possible that in the breaking 

 down and building up of the constituents of protoplasm, the products 

 'resulting combine with the poison and consequently place a limit upon 



1 Eine neue Theorie uber die Ursachen einigen Nervenkrankheiten insbesondere der 

 Neuritis und Tabes, Leipsic, 1899, und Deut. med. Wochsch. Nos. 45, 49, 52 (1904) ; 

 Nos. 1 and 4 (1905). 



