372 Journal of Coinparativc Xcnrology and Psychology. 



fHSrtl, J. Leber deii KiiiHii-> vuii \\'a>>er uiul aniM)toni>chen K()ch>alzlo>iingen 

 auf die Grunillunctit)iien der <^ueii;estreiften Mu>kelsuh>laiiz und der ino- 

 torischen Nerven. Arth. f. {Anixt. u.) PhysioL, Iahiu..i904. Heft, i-:, 

 pp. 65-93. 1904. 

 Motor nerves lose their irritability when placed in distillt'd water. 

 This can be restored by placinir the nerve for a time in hypertonic 

 ■solution of NaCl (2-3%) and then brint^nng it back into 0.5^/ NaCl. 

 Similarly, if the irritability has been destroyed by plac ing the nerve 

 in a stroniT (hypertonic) NaCl solution, it can be restored in from one- 

 half to two hours by immersiui:' the prei)aration in a hyjiotonic solution 

 of the same salt (0.2-0.3%). '^^ ''• 



Gotch, F. The Time-Relation of the Photo-electric Change produced in the 

 Eyeball of the Frog by Means of Colored Light. Jciir. PhsstcL, XXXI, 

 Xo. I, pp. 1-29. 1904. 

 The excised eyeball of the frog gives photo-electric res])onses when 

 it is subjected to the influence of colored light, however obtained. 

 These responses fail or become very feeble in the infra-red or infra- 

 violet regions of the spectrum. The range of light vibrations eliciting 

 photo-electric responses corresponds very closely with the range of vis- 

 ion in man's color sensations. The capillary electrometer gives records 

 from which the time relation of the response to a given color may be 

 determined. A response of the same general type as the illumination 

 response is obtained when light is suddenly replaced by darkness. 

 The excitatory process is of one fundamental type and is characterized 

 electrically by a difference of potential between fundus and cornea of 

 such character that a current flows through the eyeball from the for- 

 mer to the latter. There is a distinct difterence in the latent periods 

 of the response to different colored lights. The response to red 

 light has the longest latent period (ca. 0.3 second) ; the violet light 

 response has a shorter latent period (ca. 0.25 second) ; the latent 

 period of the response to green light is the shortest (less than 0.2 sec- 

 ond). The results are held to be in accordance with the Youn'G- 

 Hei.mholtz theory as modified by Maxwell. r. p. 



Nagel, W. A. and Schaefer, K. L. Ueber da< Verhalten Xetzhautzapfen 

 bei Dunkeladaptation des Auges. Zeit. f. Psv. u. Phys. d. Sinnescr^ant\ 

 Bd. 34, pp. 271-2S5, 1904. 



The results presented in this paper complement very prettily the 

 work already done by Piper. As is known, Piper experimented upon 

 the increase in the sensitivity of the larger retinal surfaces during the 

 process of adaptation to darkness and found that, if the sensitivity of 

 the retina adapted for light be comjxared witii that of the retina thor- 

 oughly adapted for darkness, the ratio of increase is from 1:2000 to 



