618 Journal of Applied Microscopy. 



Evolution in general is determined by the same factors that determine the 

 supply of nerve-endings in a tissue and the degree of their development. 



E. ISI, B. 



Eigenmann, C. H. The Eye and Hearing of P^of. Eigenmann disputes the state- 

 the Blind Fishes. Proc. Ind. Acad. Sc, ment made by Cope with regard to 



i8q8. pp. 242-24 -J ; 2 pis. » 1 1 . 1 1 r 



^j^j^jyQpg^g^ ^j^^^ ^j^g presence of an 



enemy can be discerned only through the medium of hearing. He has tried 

 whistles, tuning forks, clapping of hands, shouting, and found that noises of all 

 kinds were disregarded, although the ear of Amblyopsis is normal in structure- 



E. M. B. 



Meyer, Dr. Semi. Ueber Centrale Neuritenen- The writer protests against various 

 digungen. Archiv. f. Mikr. Anat. 54: 296- views expressed by different investiea- 

 ■?ii, Tf. 17, i8qq. ^ . , , r • 



tors concernmg the nature and function 



of the pericellular network. He considers that it is the central termination of 

 neurites, which, coming in this way in the closest contact with the surface of the 

 cells they surround, facilitate the reception of stimuli by the cell. 



Evidence against the theory suggested by Golgi, that it is an insulating 

 medium, is found in preparations in which the neurite may be traced directly into 

 the network. That the appearance is not due to the reticular structure of the 

 protoplasm is shown by sections of nen^e cells in which the network does not 

 penetrate, but may be clearly seen to stop on the surface. Material was prepared 

 after Bethe's methylen blue method, so that none of the appearances observed 

 could be due to precipitate of metal, as some students contend. e. m. b. 



n„.. „ ..L.^^K* T^- T r A Tj ■ Motion was not affected by removal of 



oetne, Albrecbt. Die Locomotion des Hai- •' 



hsches (Scyllium) und ihre Beziehungen zu portions from one side or from both 



den einzelnen Gehirntheilen und zum Laby- gj^es of the cerebrum. Removal of 



rinth. Archiv f. Physiol. 70 : 470-493, 2 



text figs., 1899. the 'tween-brain increased spontaneous 



motion, but aside from this restlessness 



no change was observed. Removal of a portion of the cortex from the posterior 



side of the corpora bigemina through the base of the mid-brain causes the fish 



to swim toward the side opposite that operated upon, and in time this is followed 



by the bending of the body in the same way, until finally the head may touch the 



tail or lie under it. When the mid-brain is entirely removed, the fish moves 



toward the left or the right, or in some cases swims on its back, although it will 



finally turn over. The statement of Steiner that spontaneous motion is lost after 



the operation, was not sustained by the experiment. 



The medulla was removed from several specimens, and in every case the fish 

 swam with rh}thmical motions, although somewhat inclined to reel. Stimulation 

 of these specimens stopped swimming motions except when the medulla had 

 been cut between the auditor}- and the glossopharyngeal nerve. 



Correlated motion is undoubtedly influenced by the labyrinth. Longitudinal 

 division of the medulla affects the geotropism of the fish, and this division plus 

 hemi-section in the posterior part produces effects similar to the sectioning of 

 the auditor}- nerve, but the effects are less pronounced. Cutting the auditory 

 nerve on one side has but slight effect if the medulla is partly cut through in the 



