8 Stbucture of Neurones in Nervous System of White Rat 



observed by Semi Meyer (1896), Held (1897), Ramon y Cajal (1899), Golgi and his 

 students, and others. 



In certain kinds of neurones the present writer has also been able very clearly 

 to see these phenomena in his preparations. The cerebellar cortex is a most favorable 

 locality in which to see the termination of the axones on the cell-body. It is a well- 

 known fact that the Purkinji cells are surrounded by the terminals of the collaterals of 

 the so-called basket cells, located in the molecular layer. Fig. 5 (Plate XIV) illustrates 

 these terminations. In this figure the Purkinji cells are represented in sepia and the 

 axone endings by a deep red. As can be seen, a large number of the neurosomes 

 appear surrounding the basal portion of the cell-bodies together with their axones, and 

 form a basket ; while the upper part of the cell-body is in contact with a small number of 

 the neurosomes along the cell-wall. According to the existing view, the basket-forming 

 fibers are derived only from the collaterals of the axones of the cells which lie in the 

 molecular layer. Contrary to this view, the writer believes that the fibers which form 

 the basket have at least two sources of origin : that is, one from the molecular cells and 

 the other from the so-called moss-fibers. This conclusion was drawn from the following 

 evidence : by examining Fig. 5 (Plate XIV) one can easily see that the main part of the 

 fibers which form the basket including the basal portion of the Purkinji cells descend 

 toward the medullary layer and become continuous with some of the fibers in that layer. 

 In other words, some of the fibers which enter into the granular layer enlarge very much 

 and ascend as far up as the Purkinji cell layer, where they surround the latter very 

 intimately and form the so-called "basket" in company with the descending collaterals 

 from the cells in the molecular layer. In the same figure the sections of the main 

 trunks, as well as the lateral branches of the moss-fibers in various planes, are shown 

 distributed throughout the granular layer. In many cases these cross-sections of the 

 moss-fibers are surrounded by the neurosomes which stain lightly. These structures, 

 formed by the two kinds of the neurosomes, correspond probably to the glomeruli ; and 

 the neurosomes which stain lightly are identical with those which form the dendritic 

 branches of the granular cells, while the rest of the neurosomes are those which form 

 the moss-fiber. 



An appearance similar to the basket of the Purkinji cells has been observed by 

 the writer in the case of the cells in the Ammon's horn. Fig. 4 (Plate XIII), which 

 has been drawn from the cells in the Ammon's horn, in the adult white rat shows the 

 basal portion of the cell-body densely surrounded by the axones of another neurone 

 forming a pericellular network. 



The termination of the nerve-fibers on the cell-body in the corpus trapezoideum 

 has been described by several investigators, especially by Held (1895). In the case of 

 these neurones, according to him, the terminals of an axone come into contact relation 

 with the cell-body of another neurone, yet one can always make out where the proto- 

 plasm of one neurone ends and where that of the second begins. Further, the line of 

 demarkation is more refractive than the adjacent protoplasm. He finds, however, that 



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