Meyer, Data of Modetn Neurology. 287 



rally adopted views to the study of embryonic material. He 

 stands firmly on the ground of His as far as the primary origin 

 of neurones goes, but establishes concrescences in the adult. 



Anyone who examines the excellent drawings of Held and 

 the account of his technique must admit that his data cannot 

 be refuted by the available literature. However improbable his 

 results seem, they seem so largely because for years we have 

 with all our efforts tried to get rid of old views, gained less on 

 ground of minute observation on all kinds of material than on 

 the one which did best justice to the new demands. This was 

 the embryonic material concerning which Held says explicitly 

 that anastomoses could not be observed yet. 



Personally, I cannot change from one view to the other as 

 if I never had any, and I feel rather sceptical toward certain 

 claims of Held, but certainly not to much so to not consider it 

 unwise to disregard his findings. They appeal to me because 

 they are at last again studies of tissues and not merely studies 

 of 'cell-individuals' disregarding everything in the section that 

 does not fit into the customary plan. It will however be neces- 

 sary to prove the same conditions by preparatians gained with 

 the ' fibril methods ' of the future, before we can call ourselves 

 convinced.^ 



With this view we must close the data we have on hand 

 for the neurone-theory. The fact that Wiedersheim once saw 

 motion in the nerve-cells of Leptodora hyalina and that certain 

 differences in the tissues of the retina and nervous system dur- 

 ing rest and activity have been observed, is in altogether too 

 problematic a state to be discussed here. The reader is referred 

 to van Gehuchten, 2d edition, p. 218-222. 



* Since this was written (May, 1898), NissI has repeatedly announced that 

 the neurone-theory has died under the weight of Apathy's and Bethe's discov- 

 eries. We shall take occasion to analyze his leasons for the return to a diffuse 

 network, which, after all, is merely a 'fibrillary' edition of Golgi's reseau ner- 

 veux diffus. 



