Literary Notices. xxiii 



as Engelmann assumed (retinomotor fibres.) Gotsch and Horsley have 

 found that irritation of the dorsal root fibres of the cord produces neg- 

 ative variation in the corresponding fibres of the opposite side. This 

 suggests the possibility of the transference from one sensory path to 

 another. 



His, Herrick, Monakow, Cajal and others have demonstrated in 

 various groups the existence of centripetal and centrifugal tracts. (See 

 also Wlassak, Die Optischen Leitungsbahen des Frosches, in Archiv 

 f. Anat. u. Phys., 1893, Suppl. to Phys. Part, who makes the rela- 

 tions clear in the frog itself.) 



Three positions of the cones are distinguished, a proximal, inter- 

 mediate and distal. In the proximal position the average length of 

 the myoid, or terminal portion, from the limitans externa to the prox- 

 imal end of the ellipsoid, is one or one and a half the length of the 

 ellipsoid itself. The spheroid of the cone lies near, generally above, 

 the limit between inner and outer segments of the rods, at any rate all 

 within the lower third of the space between limitans externa and the 

 under surface of the bodies of the pigment cells. 



In the intermediate position the majority of the ellipsoids lie in 

 the middle third of this space and their myoids are narrow and two to 

 four times as long as the ellipsoid, while in the distal position the ellip- 

 soids occupy the upper third of the space and have a slender thread- 

 like myoid. Irritation of one eye with salt solution while the optic 

 nerve remained intact, caused the ellipsoids in the other retina to 

 assume the proximal position in 86.6 per cent, of the cases, while if 

 the optic nerve had been resected only 24 per cent, were in this posi- 

 tion. The exceptions are explained in various ways. 



Direct irritation of the optic nerve or chiasm produced proximal 

 position of the ellipsoids in 82.3 per cent, of the experiments while 

 in control cases only 18.4 per cent, were found in this position. 

 These experiments are thought to afford physiological support to the 

 anatomical theory of centrifugal fibres in the optic nerve. 



The Structure of the Electric Organ of Torpedo. 1 



This elaborate monograph on the nervous termini in the electric 

 organ cannot be condensed for review here. It details the results of 

 extended applications of the Golgi method to these organs and claims 

 to set at rest many of the moot points. A considerable portion of the 



a BALLOWiTZ, E. Ueber den Bau| des Elektrischen Organes von Torpedo, 

 etc. Arch.f. tnikr. Anat. XLII, 3. 



