176 Journal of Comparative Neurology. 



short side branches, they are nevertheless of a very regular 

 contour. If the same preparation is set aside for a short time, 

 10 to 15 minutes, and is again exposed to the air by the removal 

 of the cover glass, and then again examined, small blue granules 

 and now then an axial thread may be seen in many of the end- 

 branches of the axis cylinder. 



In tissues fixed in ammonium molybdate, sectioned and 

 double stained in alum carmine, the branches of the axis cylin- 

 der present different appearances. In some motor endings. 

 Fig. 3, a distinct axial thread and stroma may be made out; 

 this is, however, only rarely seen. More often the branches of 

 the axis cylinder present a fine granular appearance ; irregular 

 granules varying in size and the intensity with which they are 

 stained, and distributed, sometimes evenly through the end- 

 branches, or again only in their peripheral portion, may be seen. 

 Fig. 4 to 8 show this. It may in fact be stated that the end- 

 brush of a motor nerve, meaning by that the branched ending 

 of an axis cylinder in a motorial end-plate, is structurally very 

 similar to the nerve fibers and their branches in other nerve end- 

 ings when stained in methylene blue and fixed in ammonium 

 molybdate. We are therefore led to conclude, basing this state- 

 ment on a somewhat extended experience with the intra vitam 

 methylene blue method, that the differentiation which has been 

 observed and described, in the structure of the end-brush of a 

 nerve fiber ending in the motorial end-plate, depends, to some 

 extent at least, on the method used to stain it; and, if the meth- 

 ylene blue method is used, on the time intervening between 

 their successful staining and their fixation, and also on the fixa- 

 tive used. In this connection, it may further be said that a 

 comparison of the figures given by observers using the meth- 

 ylene blue method in staining the motor endings with those 

 current in our text books and with Kiiline's excellent and num- 

 erous figures will show that the branches of the axis cylinder 

 appear much smaller in methylene blue preparations than in 

 those stained with gold chloride ; the former method, it would 

 seem, portrays much more nearly the actual conditions. This 

 at least seems to be the case when such motor endings are com- 



