944 THE LUMBAR ENLARGEMENT OF THE SPINAL CORD. 
more or less from this angle, sometimes curving round and taking a direction nearly 
transverse before entering the cornu, or, as is sometimes the case, one or two of the 
fibres enter some one of the cells situated just at the border of the gelatinous sub- 
stance; usually, however, these bundles curve still more upwards, assuming finally a 
direction nearly longitudinal, in which case it becomes extremely difficult to follow 
them; for although they can often be traced a very considerable distance, and are occa- 
sionally seen to enter the gray substance, more frequently they are hidden by bundles 
which cross them, or terminate suddenly, being cut across by the section. It is there- 
fore quite impossible to say with absolute certainty whether all these fibres enter the gray 
substance, or whether part of them are continued upwards to the brain. Many of them 
may be traced directly into the gray substance, and most of the others converge very 
gradually, but steadily, towards the same destination, so that, if any fibres continue 
their longitudinal course upwards to the brain, the number must be very small, by no 
means sufficient to conduct all the sensitive impressions, as Schrúder van der Kolk has 
imagined. When we examine the descending oblique bundles, we shall see that some of 
these pursue an equally longitudinal course; but surely every one would admit that 
these must enter the gray substance, rather than be prolonged down into the filum 
terminale. It is therefore highly probable on theoretical ground, and our observations 
point strongly in the same direction, that all the ascending fibres enter the gray sub- 
stance; still it is to be remembered that this is not yet anatomically proved, if indeed it 
ever can be. "This conclusion is also fully in accordance with the physiological experi- 
ments of Brown-Sequard* and Schiff,+ proving that all the sensitive fibres enter the 
gray substance within a distance of a few centimeters at most from their starting-point. 
Intermixed with the oblique ascending fibres may be noticed a variety of bundles, 
which, instead of pursuing an oblique course, become nearly longitudinal very soon 
after their entrance into the column, often following a wavy course, interlacing in a 
very curious manner with the transverse and oblique bundles (Fig. 8, J, f), doubtless 
serving to convey sensitive impressions to portions of the cord situated at quite a dis- 
tance above the entrance of the root. These bundles may sometimes be followed 
through a gradually converging course into the cornu. 
The fibres of the second class, or transverse fibres (Fig. 8, e, e), vary but little from 
this direction; they usually enter the cord as part of some other bundle, depending 
upon it somewhat for their after course, ascending or descending slightly according to 
their derivation from ascending or descending bundles. They are sometimes connected 
* Comptes Rendus de la Soc. de Biologie, 1855. Journal de la Physiologie, Jan. 1858. 
f Lehrbuch d. Physiologie, 1858, p. 250. 
