it includes matched calomel half-cells connected by saline-agar bridges to a corneal contact lens on the eye and a reference chamber on the forehead , a low-drift differential-input d.c. amplifier , an a/d converter , a computer , a thermoprinter , a flexible disc memory , a plotter , and a device for light stimulation controlled by the computer .
C0015392
eye
C0003151
chamber