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reaction ciiul rejiiener^tion varies of course according to many anatomical 

 a]id piiysiological circumstances. It is very probable that there are 

 cells from which a callosal fibre originates as ^^ wZ/^ü^t^yvü/, among- those 

 which are found to be injured. 1 am, for instance, inclined to include 

 herein some star-shaped cells betw^een the broadened lamina IV of 

 the area striata, perhaps even cells from the polymorphic lamina VI. 

 It should, however, be borne in mind that similar changes — espe- 

 cially the presence of glia-elements in diiferent stages of activity — 

 also occur where tibres and fibre-terminations have degenerated. The 

 studying of medullary-sheath preparations, cannot fully trace the 

 course of these last. The circumstance that a clearly iieightened 

 activity of the neuroglia cells was met with, also where there was 

 but little to be seen of ganglia cell changes (lamina IV and even 

 lamina III, cat), makes it probable that callosal fibres also rise 

 as far as, or even above, the inner granular kiyer. That they, 

 moreover, on theii' course thither, give off end-collaterals in the 

 deeper layers V and VI, may be concluded from the same glia-position 

 being found in similar circumstances. 



As to the manner of connection of the two hemispheres, i.e. 

 wiiether the callosal fil)res run oidy between symmetrical [)laces or 

 whether thcv connect dissimilar cortical regions, no cei-tainty could 

 be obtained tVoui the above experiments. Positive secondary changes 

 in regions which wei-e separated by the operation from the symme- 

 trical tracts of the other hemisphere, I have not found, not even in 

 the case of lesion of the cortex. Experiments of the latter kind are 

 probably not delicate enough. 



The results of partial cutting of the psalterium can be more 

 easily reviewed. The only absolutely clear results were the changes 

 in a part of the Amnion's pyramids, as described and illustrated, 

 and which without doubt are of a temporary nature. The extremely 

 slight glia-spreadijig in the secondarily -injured region is remarkable. 

 It may be inferred from this that the psalterium, in so far as this 

 lies between the two amnion's formations, under the caudal and 

 medial part of the corp. call., consists of fibres which are collaterals of 

 other fibres (timbria, fornix). Where they end could not be determined 

 by my experiments. 



With regard to the course taken by the fibres of the constituents 

 of the corpus callosum, the exjteriments demonstrate that this in the 

 cat and rabl)it inclines strongly towards the dorsal and dorso-lateral 

 regions of the hemisphere. 



A tapetum corp. callosi is only formed on the lateral ventricle; 

 where the latter, moreover, also absorbs the lower horn (considered 



