345 



liave certainly nothing to do with forced movements and secondary 

 vestibnlarj' connections. Very instructive is fui'thermore the comparison 

 of 90 and 92 ; in both cases both P.I .B. are cut through, but in 

 one case simultaneously the right F.D.A., in the other one the left 

 F.D.A. is severed. The rolling movements in ail these animals were 

 to the side of the F.D.A. that was degenerated, in toto or in the 

 lateral part. 



All lesions in this undergroup, are found in the F.D.A. between 

 the proximal part of the DKiTERS-CompIex to the oral termination 

 of the F.D.A., lateral to the trochlear nucleus. A destruction of the 

 distal parts of DEiTERs-complex (95) causing no degeneration of this 

 area, I hold that the fibres of the F.D.A. arise in the medial and 

 proximal cellgroups of Deitkrs nucleus. Lewandowsky and C. Winkler 

 also indicate, that the Fasc. Deiters Ascendens exhausts itself in the 

 4'*' and 3^' nuclei. 



For comparison also J 39 is placed in this series, because in this 

 animal, exclusively the left posterior longitudinal bundle was cut, 

 resulting in uncommonly long lasting circusmovement to the right 

 side (10 days). There was however no trace of rolling movements. 

 In the second undergroup (group IV) four animals are brought 

 together, in which rolling movements to the normal side were 

 observed after direct lesion of the F.D.A. Also in these animals it 

 could be practically excluded, that the N. vestibularis or its Nuclei 

 were hurt and could be held responsible for the forced movements, 

 observed during life. As in these animals (158, 91, 68, 221 and 

 also 5 (EcoNOMO and Karplus)) we find excluisively degeneration of 

 the medial part, of the F.D.A., I think we may infer that in this 

 part of the areal fibres are abundant, which represent the ascending 

 connections of the Ramus descendens Nuc. Vestibularis. It will be 

 recalled, that a lesion in this latter cellgroup causes equally rolling 

 movements to the normal side. It is interesting that in cat 68 a 

 maximal i-otation of the head tow^ards the normal side was observed, 

 being a result, I consider, of the haemori-hage, that was located in 

 the middle part of the F.D.A. 



In a scheme I have tried to render conspicuous the results of 

 this investigation. If we compare these data of the physiological 

 analysis of the ascendent connections of DEiTERS-complex, with what 

 we know from Fi,ourens, Spamer, Cyon. Ewald, 'Baranyi, Ca mis and 

 others about the function of the semicircular canals, there can be hardly 

 any doubt, that for the rolling movements, we have to look to the 

 anterior vertical canal as its source of centripetal im])ulses. As we 

 have found two bundles in the F. D. A. of which a lesion causes 



