12 Structure of Neurones in Nervous System of White Rat 



endocellular network is really homologous to the canal system described by Holmgren, 

 it should occur along the cell-periphery where this canal system is most abundant as 

 well as larger in diameter. Further, as has been pointed out by Soukanoff (1902), 

 these two structures do not show any similarity in appearance. 



The present writer thinks also that the anastomosis of fibrils of Apathy within the 

 cell-body may be a homologous structure to both Golgi's endocellular network as well 

 as to the network here described. Judging from its manner of distribution and posi- 

 tion in the cell-body, they are nearly identical with one another. Slight variation 

 in the structure depends upon the tissues taken from animals which are widely 

 different. The more complex anastomosis of Apathy are due to the greater accuracy 

 of technique. 



It seems to me, therefore, that the fundamental structure of the ground substance 

 in the nerve-cell shows reticular arrangement, which, however, becomes sooner or later 

 elongated, and thus the fibrillar appearance in the axone hillock, axone, and dendrite, 

 and the complicated anastomosis in the cell-body, are brought out in the way previously 

 described. 



As will be seen from the previous description, certain nerve cell-bodies, such as 

 Purkinji's, the pyramidal cells and the cells in the corpus trapezoideum and ventral horn 

 of the spinal cord, are densely surrounded by the terminals of the axones, and in some 

 cases not only surrounded, but some of the axones terminate on the cell -body and 

 become contiguous with it. Further, the dendritic processes, especially the gemmules, 

 are as a rule very densely surrounded by the axone terminals. In all these cases, 

 however, those two kinds of structures are merely in contact with each other, and the 

 present writer was not able to see any actual continuity between the two. Even in the 

 case of the olfactory glomeruli, where the axones and dendrites unite and form a single 

 filament, these two structures can nevertheless be clearly distinguished. I conclude, 

 therefore, that, although the two structures appear continuous with one another, never- 

 theless the junction point can always be recognized by the differences in structures in 

 either side of it. 



BIBLIOGRAPHY 



ApItht. " Das leitende Element des Nervensystems und seine topographischen Beziehungen 



zu den Zellen," Mittheil. d. Zool. Stat, zu Neapel, XII, 1897. 

 Ballowitz. " Ueber das Vorkommen echter peripherer Nervenendnetz." Anat. Anz., IX, 1893. 



" Die Nervenendigungen der Pigmentzellen." Zeitschr. f. wiss. Zool., LVI, 1893. 

 Barbacci, O. " Die Nervenzelle in ihren anatomischen, physiologischen und pathologischen 



Beziehungen nach den neuesten Untersuchungen." Centralbl. f. allg. Pathol, u. pathol. 



Anat., X, 1899. 

 Barker, L. The Nervous System and its Constituent Neurones. New York, 1899. 

 Becker. " Haematoxylin-Kupfer Farbung der Nervenzellen." Arch. f. Psychiatrie, XXVII, 



1895. 



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