343 



Rabbit I in group 2 of' van Valkenburg is iiüeresliiig. Tiie bmin was 

 staijied after Weigekt-Pal. Besides the atrophy of Gudden's nucleus, on 

 the side of tiie lesion, described some lime ago, in a reconsideration of 

 the series of slides this author and myself could convince us of a 

 decided diminution in size of the same sided P. L. B. -formation, in 

 the pontine and medullary region. This case, therefore seen the 

 decided tendency to roll to the right side, as noted down by Dr. van 

 Valkenburg, comes in the line, I think, of experiments 107 and i 08, 

 in suggesting the possibility, that the tr. interstitio-spinalis might 

 represent the descending limb of the reflex-mechanism, dealing with 

 the rolling to the intact side ; in the same way as, after my former 

 communication (October 1912) the commissuro-medullary bundle 

 represents the descending limb of the reflex-mechanism, controlling 

 the circus movement to the side of the lesion. 



Next follow in my table three cases, where the region of Deiters 

 Nucleus was wounded and at the same time the vestibulary radiation 

 on one or on both sides was not found free from degeneration ^). The 

 rolling movements, observed in these cases (in its rudimentary 

 manifestations lying on one side, falling to one side, rotation of 

 the head around the neck to one side) agree with those observed 

 after lesion of the vestibnlary nerve. 



As in these cases we have to deal with a gross lesion of the 

 nuclei, the secondary ascending DErrERs-connections are not found 

 free from degeneration. Again, for the anatomical-physiological ajialysis 

 these cases are of little use, as such complicate lesions do not allow 

 of any safe conclusion. 



After my former communication about the circusmovement, which 

 disturbance in its pure form was never observed by me as a result 

 of direct lesion, we cannot but ascribe the circus movement to the 

 right side in J 13 and 118 to the lesion of Dejters Nucleus on the 

 right side and the degeneration in the crossed ascending P.L.B.- 

 Bundle. 



Complicated lesions we find also in group 3. It cannot be said 

 that in any animal one cellgroup only, of Deiters Complex was 

 hurt. Solely in VIII and 99 we find a lesion limited to the Ramus 

 Descendens of the Vestibular Nucleus. Here it is remarkable, that 

 both animals, notwithstanding important differences in extension of 

 the lesion, yet have shown the same type of rolling movement, viz. 

 to the normal side. Here it must be recalled, that in none of my 

 experiments with direct or indirect lesion of the nerve itself this 



1) This is the reason why il is not possible to attempt in this sort of experi- 

 ments the physiological analysis of the different parts of DEiiERS-Goraplex. 



