( 13 ) 



collaterals in the course of the axon between the cell and the lesion 

 are probably the principal of these. It is therefore even possible that 

 after a certain interval scarcely any cell degeneration would be found 

 as a result of the cutting- of callosal fibres. 



I experimented upon cats and rabbits. I divided the whole corpus 

 callosum, or parts of it, in a sagittal direction, either in the middle 

 line, without injuring the hemispheres, or close to the sagittal medial 

 plane through the dorsal cortex on one side. In the latter case I 

 examined the uninjured hemisphere principally for cell alterations, 

 the other was stained after Wkigert-Pal and van Gieson. 



I will communicate in this paper the results of two callosum 

 operations: one on a cat, whose caudal callosum-half was divided, 

 and one on a rabbit, where the same operation was performed in 

 the frontal half. 



Cat 3. Operation: March 22"^^ 1909. 



In a small-sized, full-grown cat a sagittal section was made through 

 less than the posterior half of the corpus callosum, including the 

 splenium. The medial wall of the left hemisphere was slightly injured. 

 During the first few hours after the operation, the cat showed a 

 tendency to turn to the left in walking. The next day the animal 

 was listless, it did not move with the natural agility, while the left 

 pupil and eye slit were larger than the right. At the end of a week 

 the cat did not show any morbid S3'mptom ; it was killed 4 months 

 later. 



The post-mortem examination showed the following data: 



The length of the corpus callosum is 12 mm.; it was divided 

 sagittally in its posterior part from the caudal end till the trans- 

 versal plane of the caudal border of the medial part of the fissura 

 cruciata (1 mm.;. The fibres of the psalterium in this region had 

 been equally cut : the thalamencephalon and the mesencephalon were 

 uninjured. IV2 vnm. behind the frontal end of the lesion a superficial 

 malacia of the dorsomedial cortex of the left hemisphere began, 

 which extended 8 mm. in a caudal direction, i.e. 2^2 mm- behind 

 the transversal plane through the posterior border of the splenium ; 

 the underlying white substance of the gyr. splenalis was for a small 

 part, and then only superficially, softened. 



It may be stated that in undoubted connection with the described 

 cortical lesion, which in its caudal part was localised in the frontal 

 third of the area striata — as pointed out by BR0DMA^N Campbell e.o. — 



1) MuRATOFF : Secund. Degenerat n. Durchschneidiing des Balkens N. Ztrbl. 1893 

 Lo Monaco è Baldi : Sulle degener. conseg. al taglio longitud. del corp. call Arch, 

 d. farmac. speriment. Nov. 1904. 



