845 
made alterations proximally in the lateral geniculate body and -dis- 
tally in the occipital lobe. 
As the reproduction of the Wericerr—Pat preparation !) (fig. 6 and 7) and photo 
1 and 2 show, the two foci are thus situated that the older cuts the dorsal 
division of the strata sagittalia over the whole width. 
This fceus — the important one of the two — reaches close up to the lateral 
geniculate body (fig 6, pointed out by the first line through fig. | and 2) and 
stretches, cutting through the strata sagiltalia, along the dorsal boundary of 
the cornu inferius and posterius (fig. 7, pointed out by the first following line 
through fig. 1 and 2), where the fresh focus too is found. It ends about 2 e m. 
proximally from the distal end of the cornu posterius. Nowhere the ventro-medial 
division of the strata is affected directly by the focus. In fig. 6 and in fig. 7, 
this is intact. 
According to the destruction by the focus, totally different fibre-systems are 
affected and a massive degeneration towards the occipital pole takes place. 
The degenerated mass of fibres has been drawn on a more distally situated 
seclion (s fig. 8, line 8 through fig. 1 and 2) 1 c.m. distally from the focus !). 
In this is visible, that the tapetum-fibres are very soon restored after their trans- 
section, showing nearly a normal tapetum and forceps posterior round the very 
wide ventricle. In a less degree this is also the case with the stratum sagittale 
internum. It has fewer fibres than normal, and between them are spread dege- 
nerated fields in different spots. But the loss of fibres in the stratum sagittale 
externum is enormous. No normal fibres are to be found in it. This mighty black 
layer in WetcertT—Pat preparations is here replaced by a while band, as well 
in the dorsolateral as in the ventro-medial division. 
Smaller white stripes, coming from the degenerated band round the ventricle 
penetrate to far into the medullary cones of the convolutions, surrounding the 
calcarine fissure, also to the praecuneus and to the gyrus angularis, The gyri occi- 
pito-temporalis and fusiformis have suffered least. 
The massive degenerated ring round the ventricle is always found distally from 
the ventricle-end till the occipital pole. About !/, e.m. behind this end (s. fig. 9, 
line 9 from fig. 1 and 2) the distal point of the restored stratum sagittale inter- 
num is still touched and lies as a black island within the white degenerated mass 
of the stratum sagittale externum, while nearly all the medullary cones of the 
convolutions are degenerated and only fibrae arcuatae seem to be left. . 
The praecuneus has suffered least. In the section, which falls about 1 ce m. from 
the occipital pole (s. fig. 10, last line througli fig. 1 and 2) it is hkewise. From 
the massive centre degenerated stripes penetrate in every convolution. 
All this proves that perception in the upper fields of vision is 
still possible, notwithstanding the stratum sagittale externum in the 
occipital pole is missing. If therefore the fibres, used for visual per- 
ception are to be looked for in that layer, as seems probably to me, 
1) Al these figures have been drawn with the greatest care; they are enlarged 
21/5 times and reduced to 7/9 of their size at the reproduction. Photos would 
have shown the same things, but drawings are more instructive as combinations 
of several sections are possible. 
