INORGANIC RESPONSE 157 



responses, which show very little sign of fatigue. How 

 similar these response-curves are to those of the retina 

 will be seen from a pair of records given below, where 

 fig. 99 shows responses of frog's retina, and fig. 100 

 gives the responses obtained with the sensitive silver 

 ceU (fig. 100). 



It was said that the responses of the retina are 

 uniform. This is only approximately true. In addition 

 to numerous cases of uniform responses, Waller finds 

 instances of ' staircase ' increase, and its opposite, slight 

 fatigue. In the record here given of the silver cell, 



FIG. 100. KESPONSES IN SENSITIVE SILVER CELL 



Illumination for one minute and obscurity for one minute. Thick line represents 

 record during illumination, dotted line recovery during obscurity. 



the staircase effect is seen at the beginning, and followed 

 by slight fatigue. I have other records where for a. 

 very long time the responses are perfectly uniform, 

 there being no sign of fatigue. 



Another curious phenomenon sometimes observed in 

 the response of retina is an occasional slight increase of 

 response immediately on the cessation of light, after which 

 there is the final recovery. An indication of this is seen 

 in the second and fourth curves in fig. 99. Curiously 

 enough, this abnormality is also occasionally met with in 

 the responses of the silver cell, as seen in the first two 

 curves of fig. 100. Other instances will be given later. 



