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 
cell (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, 

Fic. 100.—ReEsponses 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 shght 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 onthe 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. 
