?46 MESSRS. F. GOTCH AND V. HORSLEY 



SEMON and HORSLEY* observed that in all animals examined, i.e., Rabbit, Cat, 

 Dog, and Monkey, the bilateral movements of the vocal cords were still perfectly 

 obtained on excitation of the one cortical representation after that of the opposite 

 side had been removed. 



4. Excitation Experiments on the Cortex combined ivith Hemisection of the Spinal 



Cord, &c. (ECKHARD'S Method). 



FRANCK and PrTREst observed that in the Dog hemisection of the spinal cord on 

 the same side as that of the hemisphere excited failed to abolish the bilateral move- 

 ments in the limbs. 



LEWASCHEWJ followed the French authors by similar experiments in the Dog, from 

 which he deduced the same idea, viz., that the bilaterality was accomplished by means 

 of commissural fibres in the spinal cord. 



BALIGHIAN observed that in the Eabbit the opposite, i.e., normally corresponding, 

 movements were not abolished by hemisection of the bulb opposite the lower border 

 of the pons and on the same side as that of the hemisphere excited, whence he con- 

 cluded that the crossing of the excitable fibres begins to occur as high as the lower 

 border of the pons. 



BALIGHIAN also showed that in the Rabbit, excitation of one hemisphere failed 

 to elicit movement in the opposite limbs if the corresponding part of the spinal cord 

 had been divided. 



SCHIFF|| found that in the Dog after section of the right crossed pyramidal tract 

 excitation of the cortex with four Leclanche elements produced no result (whereas 

 before the division this formed a maximal stimulus), and only with a current of 

 fourteen elements were movements of both the hind limbs obtained. 



GLIKYH showed by hemisection of the bulb that in the Rabbit the pyramidal tract 

 crossed below the centre of the fourth ventricle, and that a tendency towards 

 unilaterality of representation prevailed. 



STEFFAHNY,** applying this method in Rabbits, came to the following conclusions : 

 that the path of the crossed impulses for the innervation of the extensors of the fore 

 limb is in the uppermost part of the cervical cord, the anterior column, and lower 

 down in the lateral column, and further that there are paths for bilateral movements, 

 and that these lie in close relation to those for the ordinary crossed effect. 



* Loc. cit. 

 f Loc. cit. 



I PKLUGKE'S ' Archiv fur die gesammte Physiologic,' vol. 26, 1885, p. 279. 

 ECKHARD'S ' Beitriige,' vol. 7, 1875. 

 || PFLUGER'S ' Archiv,' vol. 30, 1883, p. 248. 

 f ECKHARD'S ' Beitriige,' vol. 7, 1876, p. 186. 

 ** ECKHARD'S ' Beitrjige,' vol. 12, 1888, p. 43. 



