334 
MR. E. P. FRANCE ON DEGENERATIONS WHICH FOLLOW LESIONS 
other side, but very much less in amount. This degeneration has been followed down 
the cord as far as the lumbar region in some instances. 
The shape of the degeneration in the lateral column is sufficiently constant in all 
cases where there has been considerable injury to the marginal convolution for it to be 
considered characteristic of this lesion. 
In the cervical region it is narrowly triangular or claw-shaped, the base being 
towards the posterior cornu, and the (expanded) apex at the surface of the cord, 
reaching this at about the middle of the lateral border (see fig. Ic.), One side of 
the triangle is formed by the line of separation between the crossed pyramidal tract 
and the direct cerebellar tract. Along this line tlie degeneration always appears to 
be most complete, that is to say, the degeneration is chiefly confined to the posterior 
and outer part of the crossed pyramidal tract; this is noticeable down the whole of 
the cord. In the cervical region the degeneration spreads out immediately within the 
circumference of the cord, the direct cerebellar tract appearing as if pushed backwards 
towards the apex of the posterior cornu, where it occupies an area which is triangular 
in section, in place of the oblong tract seen in sections lower down. 
In the upper dorsal region the appearance is much the same as in the cervical 
region, except that the connection of the degeneration with the circumference of the 
cord is becoming less extensive, althougii the whole tract of degeneration has 
approached a little nearer the circumference, from which it is separated by the now 
oblong cerebellar tract. 
In the lower dorsal region the degenerated tract has become less in amount and has 
approached quite close to the circumference, leaving only a narrow band of healthy 
fibres in the position of the direct cerebellar tract, and does not extend as far forward, 
although the apex of the triangle still touches the surface. There are a greater 
number of healthy fibres to be seen between the grey matter and the degeneration 
than in the cervical or upper dorsal regions. 
In the luuihar region the degeneration is very much less marked than higher in the 
cord, and occupies the angle formed by the posterior root exit and the circumference. 
In cases where the lesion in the brain had been extensive the degeneration could be 
traced as far as the fifth lumbar nerve. I have not carried sections below this point. 
Summary of Degenerations following Lesions of the Gy'RUS Fornioatus. 
The brains and spinal cords of six Monkeys, in which a part or the wdiole of the 
gyrus fornicatus liad been removed, were examined. 
In most cases the gost-mortem examination showed that the marginal gyrus had 
also been injured to a variable extent, owing, no doubt, to the difficulty experienced 
in exposing and excising a convolution so deeply situated as the gyrus fornicatus 
without interfering wdth the adjacent marginal gyrus. 
In two instances the removal of the grey matter of the gyrus fornicatus was nearly 
