THE SENSOKY PATHS 531 



the cells of the nucleus of Goll. They convey the nerve impulses 

 of muscular sensation and are chiefly derived from those nerves 

 which come from the limbs. The column of Goll, therefore, first 

 attains an appreciable size in the lumbar region, but adds to its 

 volume in each successive spinal segment through which it passes. 

 In the cervical region, this influx of fibres is so great that the en- 

 tire volume can scarcely be contained within the limits of the pos- 

 tero-internal column, and many are forced to continue their course 

 in the column of Burdach until they reach the medulla oblongata 

 where they end by arborization about the nerve cells of the nucleus 

 of Burdach. 



From the nuclei of Goll and Burdach, neurones of the second 

 order send their neuraxes ventralward toward the opposite side, 

 the larger portion taking a direct course as internal arcuate fibres 

 through the formatio reticularis alba to the raphe, where they de- 

 cussate to the opposite side and immediately turn upward between 

 the inferior olivary bodies to form the first portion of the mesial 

 fillet or lemniscus. This early portion of the lemniscus, because 

 of its position, is known as the inter olivary fillet. 



The smaller portion of the neurones of the second order from the 

 nucle of Goll and Burdach follow the indirect course, as external 

 arcuate fibres, first passing dorsalward to reach the surface of 

 the medulla oblongata, which they then follow ventralward, keep- 

 ing close beneath the pia mater until they reach the margin of the 

 pyramidal tracts, where they divide, a small portion passing between 

 the pyramids and the olivary body, a larger portion passing around 

 the ventral and mesial borders of the pyramids to reach the median 

 raphe. Here the two bundles reunite, join the internal arcuate 

 fibres, decussate to the opposite side, and enter the interolivary 

 portion of the mesial fillet. 



The mesial fillet in this portion forms a flattened band on either 

 side of the median line, its dorsal margin blending with the poste- 

 rior longitudinal fasciculus, a similar though smaller bundle of 

 association fibres which will be described under a later heading. 

 The longitudinal fibres of the fillet are spread over a sectional area 

 which extends from the mid-region of the inferior olives dorsalward 

 nearly to the hypoglossal nucleus, the posterior longitudinal fascic- 

 ulus being interposed between this nucleus and the dorsal margin 

 of the fillet. 



The mesial fillet begins at the level of the nucleus of Goll and 

 increases rapidly in size in its upward course by the constant addi- 



