vin OCULAR MOVEMENTS 399 



connected both by transverse fibres which unite the nuclei of the 

 two sides, and by ascending and descending longitudinal fibres, 

 contained in the so-called dorsal longitudinal bundle, which 

 connect the nuclei at different levels. 



Bernheimer noted that in monkeys a median incision through 

 the region of the oculomotor nuclei disturbed the synergy of 

 binocular movement each eye moved irregularly, and independ- 

 ently of the other eye ; the cells of each nucleus therefore only 

 innervate the homolateral eye-muscles. 



Different views as to the direct and indirect connections of the 

 optic nerve with the motor nuclei of the internal or external 

 ocular muscles have been enunciated by Stilling, Meynert, 

 Kolliker, Bechterew and others. Bernheimer, after enucleating 

 one eye, or dividing one of the optic nerves in the monkey, was 

 able, by Marchi's method, to demonstrate a bundle of fibres which 

 runs from the optic nerve to the anterior corpora quadrigemina, 

 and thence to the oral end of the lateral medial nucleus. As the 

 degenerated and non- degenerated fibres can be observed in 

 approximately equal numbers on both sides, this gives anatomical 

 proof that about half the fibres of the optic nerve decussate in the 

 chiasma, and that both the crossed and the direct fibres run 

 through the anterior quadrigemina towards the oculomotor 

 nuclei. 



The relations of the oculomotor nuclei with the cortex cerebri 

 were ascertained by cortical faradisation. Terrier, Luciani and 

 Tamburini, Knoll, Horsley and Schafer, and Risien Russell 

 found that stimulation of the gyrus angularis in the monkey 

 produced rotation of the eyeballs towards the opposite side, and 

 also upward and downward ; but if the stimulation is too strong 

 these eye-movements are associated with other more extensive 

 and diffuse movements of the face and head. With very weak 

 induced currents Bernheimer (1899) found that the reactions 

 were confined sharply to the eye -muscles. Stimulation of the 

 right angular gyrus particularly of the median thirds of its 

 two limbs produced synergic movements of both eyes to the 

 left, or to the left and upward or downward, and vice versa. 

 Removal of the cortex of the angular gyrus on one side is. 

 followed by obvious paresis of the eye-movements towards the 

 opposite side, which disappears almost entirely in the second 

 week after the operation. 



After Adamlik's experiments on electrical stimulation of the 

 anterior quadrigemina it was almost universally admitted that 

 these bodies represent the reflex centre for eye -movements. 

 Bernheimer, however, proved that monkeys after uni- or bi-lateral 

 destruction of these parts are still able to carry out all normal 

 movements of the eyes. Topolanski found the same in rabbits. 

 Bernheimer also showed that after this lesion excitation of one 



