132 Journal of Comparative Neurology. 



es," but the differentiation exists from the beginning, in the 

 immediate neighborhood of the nucleus itself. 



3. Most of the so-called processes of the cells are no 

 "processes," because two of them form one thread passing 

 by the cell without in any way being interrupted by the cell 

 body, as would be the case with "processes" taking their 

 origin in the cell bodies. We are not dealing with processes of 

 cells but with fibers ivhich are completely differentiated from the 

 protoplasm. They may have been processes in the embryonic 

 period only. 



This somewhat dogmatic view does not appear absolutely 

 convincing, since the " loops " are not within the contour of the 

 cell-body but fotm the outline, and many of them are outside the 

 outline and probably belong to other cells. Weigert's view 

 would seem to be the only possible one if in cells like those of 

 his Fig. I, Plate I, points of cross sections of fibrils could be 

 seen inside of the outline, such as I have never been able to 

 find either in sections kindly presented to me by Prof. Weigert, 

 or in my own preparations made with his method. 



We are not absolutely convinced of the obsoleteness of 

 the cell-idea in the neuroglia, even of the adult ; and if we 

 should become convinced of it by more strengthing evidence,* 

 we might console ourselves with the ' intercellular ' connective 

 tissue nature of this inferior substance. 



Yet, that which was thus anticipated has since been real- 

 ized by S. Apathy,^ who sees the unit of conduction in fibrils 

 ( as Gowers does in his Dynamics of Life ) passing through sev- 

 eral cells ; between fibrils among themselves and also between 

 cells he sees anastomoses — the completest revolution of the 



*F. Reinke (uber die Neuroglia in der vveissen Substanz des Riickenmarkes 

 vom erwachsenen Menschen. Arch. f. mikr. Anat, Vol. L, i8g7) corroborates 

 Weigert, saying that he has seen the true protoplasmic processes of neuroglia 

 cells, but also the absolutely different and independent fibrils of Weigert. If this 

 is true, we should of course have to bow to the evidence given. 



*Das leitende Element des Nervensystems und seine topographischen Bezi- 

 chungen zu den zellar. Erste Mittheilung. Mitth. ausder zoolog. Station zu 

 Neapel, 1S97. 



