Definition of mechanical damage of corn kernels 10 Methods of measuring mechanical damage 11 Photoelectric measuring systems 13 The dye 15 The com kernel 17 Theory of fluorescence 18 Theory of photomultiplier tubes 23 The light source 25 EXPERIMENTAL EQUIPMENT AND PROCEDURES 28 Equipment 28 The system 28 The dye 29 Fluorescent pigmented materials 30 Chemical bond fluorescence 31 Other dyes 32 The light source 33 The photodetector 34 Procedure 42 Granular dyes 42 Chemical staining 43 iii Fluorescent readings 44 Operating procedure 48 DISCUSSION OF RESULTS 50 Calibration of fluorcmeter 50 Granular dyes 51 Staining 51 Fluorescent readings 53 Chemical bonding to form fluorescent compounds 60 Preliminary investigations 60 Damage analysis 63