242 bulletin: museum of comparative zoology. 



and regarding the neurofibrillae as the structures of primary import- 

 ance, for then we should have two cell bodies corresponding to a single 

 axis cylinder, and there would be no reason for regarding the neuro- 

 fibrillae as dependent upon either cell body in any peculiar way. On 

 the basis of such embryological evidence as has thus far been adduced, 

 however, it appears that such relation as exists between the alleged 

 neurofibrillae of the sense cells and those of the axis cylinders is sec- 

 ondarily established. The embryological investigations of London 

 und Pesker (:06) to which I have already referred (pp. 218) have led 

 them to view the alleged neurofibrillae of the sense cells as originating 

 within the sense cells, and those of the axis cylinders as coming from 

 the ganglion cells. They found no evidence for the existence of fibril- 

 lae except in association with cell bodies, — either ganglion cells or 

 sense cells, which latter they regarded as wholly like ganglion cells. 



Likewise Kolmer, as I have stated on page 219, affirms that the union 

 between sense cell and axis cylinder appears to result from a growing 

 together or interlacing of fibrillae some of which originate in the sense 

 cell while others come from the axis cylinder. He believes that the 

 union between the fibrillae of the sense cells and those of the axis 

 cylinder is established secondarily, and is not the result of the growth 

 of fibrillae from the axis cylinders into the sense cells or from the sense 

 cells into the axis cylinders. He regards the sense cells as peripheral 

 nerve cells. 



Finally, the embryological evidence obtained by Bielschowsky und 

 Briihl bears out the conclusion that such union as exists between axis 

 cylinders and sense cells is secondarily established. 



In view of this embryological evidence I am not able to understand 

 why Kolmer, and London und Pesker consider it necessary to abandon 

 the neurone theory, even if all the peripheral networks which have been 

 described for this organ should meet with confirmation. They them- 

 selves regard the sense cells as peripheral nerve cells, which view is in 

 complete accord with the interpretation given them by von Lenhossek, 

 who has regarded them as short neurones. 



However, I am not yet prepared to accept these intracellular struc- 

 tures as established. The testimony to their existence is scanty and 

 inharmonious, the structure which Kolmer has described being totally 

 different from those described by Bielschowsky und Briihl, who refuse 

 to accept Kolmer's results, characterizing them as an admittedly chance 

 product, and suggesting that the appearance of the structure which 

 Kolmer has interpreted as an intracellular network of neurofibrillae 

 may be due to over heating in the warm solution of silver nitrate 

 which is used in the Ramon y Cajal process. 



