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kinaesthetic impulses, which are elaborated in the ventral unclei. The 
cortical radiation from the posterior regions of the thalamus however 
lies more backward, it is directed towards the gyrus anguiaris, 
the basal occipital convolutions and the cuneus. In this radiation 
an important degree of degeneration could be demonstrated, but the 
degenerated fibres do not penetrate into the borders the convolutions, 
surrounding the fissura calcarina. They are found in the field of the 
fovea, indicated by Nimssr.. 
Consequently, although still sufficient optical impulses join the 
cortex along the corpus geniculatum laterale and the cortical radiation 
originating from it, yet the cortex, receiving no communication as 
to the result of the elaboration of several other impulses that should 
have been prepared in the thalamus, no longer recognizes shapes 
in the crossed fields of vision. 
This analogy holds good only, in as far as the optical sense 
together with the sense of touch and the kinaesthesia renders the 
conception of shapes possible. 
The eye may also, independently of the sense of touch, recog- 
nize shapes, perceive a third dimension etc. 
Some time ago, the studies about disturbances in the perception 
of a third-dimension (Tiefen-Wahrnehmung), which are only sparsely 
scattered in literature, have been augmented with one by Dr. van 
VALKENBURG. Bilateral foei in the gyrus angularis had determined 
this disturbance, together with other symptoms, among which alexia. 
Although the perception of a third dimension has some relation 
with the recognizing of shapes in two dimensions, yet it is distin- 
guished from it, as it is likewise from stereoscopic vision. 
After the demonstration of vaN VALKENBURG I think it needless to 
argue this point, 
Necessary it is however to recall to mind an interchange of thought, 
that occurred about this subject between Dr. Nimssr, and Dr. van 
VALKENBURG ') viz. whether the dorso-lateral region of the strata 
sagittalia may contain a special fascicle of fovea-fibre. I have stated 
already that in my opinion, this is not the principal question. The 
chief point appears to me the question, whether there may be made 
a division between a light-perceiving field around the f. calcarina and 
another field enclosing the former, within which, occasionally with 
the aid of the first field, shapes are recognized. 
1) CG. T. van Vatkensure. Zur Kenntnis der gestéhrten Tiefen-Wahrnehmung. Deul- 
sche Ztschr. für Nervenh. Bd. 34. S. 322. 
NiessL von MaAyenporrr. Einige Bemerkungen zu dem Aufsatze des Herrn Valken- 
burg. lbidem Bd. 35. S. 165. 
Van VarkenBure. Kurze Erwiderung auf die Bemerkungen ec. Ibidem Bd. 35. S. 472. 
Gi? 
