24 
consequence of the increase of response after longer darkening. 
Fig. 2 of course first shows the dark-growth-response, which has been 
left out in Table II. 
Will the reaction begin earlier than by 256 M.C.S. by exposure 
to 1400 M.C.S.? This cannot be said with certainty, for cells adapted 
to the dark respond to 256 M.C.S. for the eye in growth more than 
to 1400 M.C.S. Moreover the question is, whether in the period of 
the dark-growth-response a light-response may be excited. 
Experiments A*. In the first + 5 min. after the darkening 1400 
M.C.S. has no effect (see curve 1 of fig. 3), so that the response to 
the dark takes place as usual. But applied after 6'/, min., light- 
growth-response already occurs, setting in therefore during the 
dark-growth-response. 
DONKER-ADAPTATIE EN LICHT — GROEIREACTIE. _ 
DONKER 
SE 
64MK} DONKER 
Fig. 3. Dark-adaptation and light-growth response. 
See further fig. 3 and Tab. III. From this it appears in the same 
way as by application of 256 M.C.S., that the reaction grows stronger 
according as the cell has been further adapted to the dark. In_ 
tig. 2 and 3 the process of the growth is dotted, in case the latter 
light-stimulus had not been applied. Especially striking is the sudden 
sharp transition to the light-growth-response (see 3rd and 2rd curve). 
