PARKER: RETINAL PIGMENT CELLS OF PALZEMONETES. 293 
eyes were in the condition characteristic for the dark, were decapitated ; 
their right optic stalks were cut off and put in a light moist chamber, 
and their left stalks, likewise cut off, were placed, as a check on the 
results of the experiment, in a dark moist chamber. After an interval 
of two hours both sets of stalks were hardened and afterwards cut and 
examined. In a corresponding way optic stalks in the condition charac- 
teristic for the light were cut off and subjected to the dark. 
The results of these experiments are shown in the following tables. 
Four Right Optio Stalks in Dark Condition cut off and placed in the 
Light two Hours. 
Complete change. | Partial change. No change. 
Proximal retinular cells . . . 0 3 1 
Distal retinular cells . 0 3 1 
Accessory cells 0 2 2 
The four left optic stalks cut from the same animals and retained, as 
a check, in a dark chamber, all presented on examination the condition 
typical for the dark. 
Four Right Optic Stalks in Light Condition cut off and placed in the 
Dark two Hours. 
Complete change. Partial change. No change. 
Proximalretinular cells . . . 1 3 0 
Distal retinular cells . . . . 1 3 0 
Accessory cells 1 1 2 
The four left optic stalks cut from the same animals and retained, as 
a check, in a light chamber, all presented on examination the condition 
typical for the light. 
It is obvious from these observations that, after the excision of an 
optio stalk, the photomechanical changes may still take place, if not com- 
pletely, at least partially, and it might be inferred from this that the 
brain exerted at least a partial influence over these changes. This con- 
clusion, however, is invalidated by the fact that in one case recorded in the 
