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Auf mich machen jedoch die Abbildungen von Johnston den Eindruck 

 eines willkürlich angenommenen Zusammenhangs von Nervenzellen und 

 -fasern." The writer has the impression that most workers regard 

 the GoLGi technique as the one procedure above all others which 

 enables us to demonstrate the origin of particular nerve fibers from 

 particular cells. In my own studies upon Golgi material I have 

 never stated a conclusion as to the origin of a tract of fibers which 

 was not based upon the clear demonstration of the origin and course 

 of individual fibers. I know that the same rule is followed by other 

 workers of my personal acquaintance. Tretjakoff has apparently 

 not realized the possibility of this rigid practice. He shows that in 

 many places the axones of cells were not stained either in the methylene 

 blue or in the Cajal preparations. In several places where the present 

 writer or others have described details which he could not see in his 

 preparations, Tretjakoff has made the charge that these details were 

 arbitrarily inserted in the drawings, that they result from errors of 

 observation, etc. A careful study of his paper, with a review of my 

 own preparations, convinces me that where Tretjakoff criticizes other 

 authors for inaccuracy or for drawing upon the imagination, the dis- 

 crepancies are due, 1) to the imperfect staining of Tretjakoff's 

 own preparations, 2) to his disregard for the differences which actually 

 exist between the species studied by dilferent authors, or 3) to 

 misunderstanding or wrong interpretation of the work of others. Some 

 examples of these things will be pointed out below. On the other 

 hand, Tretjakoff's methods were excellent for many things, he has 

 given us many beautiful figures from both methylene blue and silver 

 preparations and in many connections has added new and very welcome 

 facts. It would not occur to me to doubt that Tretjakoff has 

 drawn accurately what he has seen, but I am compelled to believe 

 that he has wrongly interpreted some of his facts and has failed to 

 see some things owing to his failure to make use of certain recent 

 concepts in neurology. 



In connection with the Miillerian cells and fibers one point of 

 considerable importance comes out of the discussions of recent authors. 

 I have regarded as Miillerian fibers only those which arise from giant 

 cells or at least large cells situated in the motor columns. The number 

 and arrangement of these cells doubtless differ in diflferent species, 

 as is evident from the accounts by Schilling, Tretjakoff and the 

 writer. With regard to the general question of Miillerian fibers I would 

 suggest that their course and behavior in the spinal cord should be 

 studied in either longitudinal sections or in entire preparations. The 



