( 298 ) 



The nucleus caudatus, the nucleus lenticularis, the capsula interna 

 and Hie frontal end of the thalamus opticus have not suffered any 

 alteration. Neither has the whole of the nucleus anterior. About 

 halfway the sections through the thalamus, the frontal commencement 

 of the focal softening' is found, as a small irregular square in the 

 nucleus lateralis (fig. 1). The hearth consist of leucocytes, lying close 

 to one another, in its wall the capillary vessels are found distended 

 and suirharged with blood-cells. 



In the following sections the hearth is rapidly expanding (see fig. II). 

 Irregularly shaped, it is situated within the ventral nuclei 1 ), destroys 

 the largest part of the nucleus ventral is b, encompasses like this 

 nucleus the "centre median" of LüYS, and enters into the ventral 

 nucleus a until near the regio subthalamic^. The "Gitterschicht", the 

 lamina medullar is externa and the regio subthalamica are untouched 

 by it; consequently both, the lateral medullary mass of the red nucleus 

 and the strata of the lemmiscus, remain free from damage. 



In the same region is found a smaller focus, as yet apparently 

 separate, (but in reality connected with the larger hearth) in the 

 principal portion of the nucleus medialis. 



A little more caudalward see lig. Ill) the hearth attains ite largest 

 extension. It is now situated in the ventral nuclei a, h and c, that 

 are almost completely destroyed, it send- a narrow branch into the 

 nucleus medialis. and proceeds straitened wedge-like towards the 

 regio sub-thalaniica, where it approaches very closely the radiations 

 of the lemniscus-fibres and intercepts these. 



Still more caudalward (see lig. 1V,j the position of the hearth has 

 become such, that the ventral nucleus ,i is left free, whilst the nuclei 

 h and c and likewise the posterior nucleus are absorbed by it. The 

 corpus geniculatum mediale forms here likewise pari of the hearth 

 but the radiation from the hracchium conjunctivum corporis quadri- 

 gemini postici into the nucleus gen. medialis is left uninjured). The 

 hearth continues by a long and narrow branch along the ventral 

 side in the pulvinar thalaiui optici (see tig. V), ending there. 



The corpus geniculatum laterale is no where touched by the hearth. 

 Neither is the so-called "Gitterschicht" of Arnold. 



From this focus secondary degenerations start into different areas, 

 these degenerations are distinguished partly by the presence of granular 

 cells, partly by the absence of medullated iibres in lighter-coloured 

 areas in preparations after the Weigkrt-Pal method. 



In the thalamus, the frontal end of which does not show any 

 degenerative alterations (see lig. I) the posterior part of the medial 



') von Monakow's nomenclature of the nuclei Thalami is followed. 



