300 Journal of Comparative Neurology. 



would think that from an analysis of the number 121 into t 

 hundred, 2 tens, and i unit, we could get any di; ect light on the 

 process of getting the sum of 30 plus 46 plus 45 ? And is it 

 not the same effort if we believe we must speak of temperature 

 fibers, muscular sense fibers, tactile fibers? — why not of hyper- 

 aesthesia-fibers ? — while we only know small differences among 

 the cells of the afferent segmental types ? Are we not forced 

 rather to think of thermic, static etc., armngements? Yet 

 Bechterew claims that the broad fibers of the posterior roots 

 serve to the muscular sense and the fine ones to the cutaneous 

 sensibility. And since we already possess the term aesthesio- 

 neura (Minot and Baker) we shall soon speak of myoaesthesio- 

 neura and dermaesthesioneura ! It will be the task of neuro- 

 logical research of the near future to go to the bottom of these 

 segmental localizations with a full recognition of the danger of 

 ' psychological ' neurology and the possibility in mind that 

 many or all the qualities of ' sensations ' and reactions are 

 products of the function of mechanisms and that the eleineiiis of 

 the ' psychical ' products are not necessarily fit to be identified 

 with the elements of the mechanism.^ This cannot, however, stop 

 our eagerness for progress and we must admit that we are in 

 perfect sympathy with the most eager localizer. Our hope for 

 the progress and future of neuropatholoLjy rests on localization 

 as a first step to the research on the nature of the lesion. We 

 vmst associate certain symptoms with lesions of certain groups 

 of neurones and we can do that without in the least becoming 

 untrue to the above principles, and, if we look closely, this has 

 at all times been the method of the more conservative. Com- 

 paring many kinds of clinical types with the sets of lesion found 



' In a discussion of biological monism some one objected by saying : On 

 monistic ground psychology becomes simply a part of neurology. To any one 

 who shares that fear I should recommend to sacrifice at once the desire for unity 

 and to keep at least the three series of experiences apart: l. The morphological- 

 anatomical, 2. The ergetic physiological, and 3. The psychical. It would be a 

 pity if a desire for monism would obscure the necessity of critically separating 

 these three series in biology. I hope the readers will accept the term 'psycho- 

 logical neurology ' as simply meaning the uncritical mixing up of facts of neuro- 

 logical and of the psychical series. 



