572 [May 21, 



c. Ganglion-cells formed by changes occurring in what appears 

 to be the nucleus of a nerve-fibre. 



3. Further changes in the ganglion-cell after its formation. 

 Under this head the movement of the cell from the point where 

 its growth commenced is described. It is shown that the two fibres, 

 which at first seem to come from opposite extremities of the cell, lie 

 parallel to each other. They increase in length, and subsequently 

 one is seen to be twisted round the other, as shown in the figure. 

 Sometimes the fibres below the point where the spiral arrangement 

 exists run parallel for a long distance, but at length pursue opposite 

 directions. The author considers that the formation of the ganglion- 

 cell commenced at the point where the fibres diverge, and that sub- 

 sequently the cell moved away, the parallel fibres, which at length 

 become straight and spiral, being gradually formed or drawn out 

 as it were from the cell. 



4 . Of the spiral fibre of the fully formed ganglion- cell. 



The spiral fibre or fibres can be shown to be continuous with the 

 material of which the body of the cell is composed, as well as the 

 straight fibre, but the former are connected with its surface, while 

 the latter proceeds from the deeper and more central part of its sub- 

 stance. 



There are many nuclei in connexion with the spiral fibre, and 

 several nuclei of the same character imbedded in the substance of 

 the mass of which the cell is composed. These latter nuclei seem to 

 be connected with an earlier condition of the matter which becomes, 

 when more condensed, spiral fibre. A great diiference is observed 

 with regard to the extent of the spiral fibre in cells of different ages. 

 In the youngest cells the fibres near the cell are both parallel to each 

 other, but as the cell grows one is seen to be coiled round the other ; 

 and the number of coils increases as the cell advances in age, while 

 the matter of which the fundus of the cell is composed gradually 

 becomes less apparently in consequence of undergoing conversion 

 into fibres. Nuclei are found in the course of the straight fibre, as 

 well as in connexion with the spiral fibre. Nuclei have been demon- 

 strated in connexion with the dark-bordered fibres near their origin 

 and near their distribution in all tissues. 



Next follows a discussion " on the essential nature of the changes 



