^^694 VERHOEFF AND BELL. 



The third experiment (Exp. 81) was similar to the first except that 

 the flint screen allowed waves down to 305 ijlh to pass and that the 

 water cell did not leak. The exposed corneal area was clear immedi- 

 ately after the exposure, but 20 minutes later was found to be 

 distinctly hazy. The epithelium at no time stained with fluorescine. 

 On microscopic examination of the eye, enucleated tliree days after 

 the exposure, the corneal stroma was found to be swollen in a rather 

 sharply defined area. The epithelium was normal. The corneal 

 corpuscles in the middle third of the cornea showed active prolifera- 

 tion, but in the posterior third had for the most part disappeared. 

 The endothelium was absent behind the exposed area. The iris and 

 lens epithelium were normal. 



In the fourth experiment (Exp. 84) a flint screen transparent to 

 waves down to 310 /x/x was used and the exposure was one and one half 

 hours. The exposed corneal area was found to be hazy within one 

 hour after the exposure. On microscopic examination of the eye, 

 enucleated four days after the exposure, the corneal stroma was found 

 very slightly swollen and to stain less strongly in eosin in its posterior 

 layers. The corneal corpuscles showed marked proliferation in the 

 posterior portion of the stroma and the endothelium was absent 

 behind the exposed area. The iris and lens epithelium were normal. 



In the fifth experiment (Exp. 90) a flint screen (Slii fxfx) was used 

 and the conditions were the same as in the first experiment with 

 the important dift'erences that the water cell was omitted and the 

 exposure was only 30 minutes. Distinct haziness of the cornea 

 was observed within 20 minutes and within 24 hours became very 

 marked. On microscopic examination (48 hours) the cornea showed 

 changes similar to and almost as marked as those of Experiment 

 88. The corneal epithelium and lens epithelium were unaffected. 



Combined Thermic and x\biotic Effects of Radiant Energy 

 ON THE Cornea. 



In four other experiments in which the exposures were prolonged, 

 both abiotic and heat effects were obtained in the cornea. The 

 screens used were transparent to waves less than 30.5 /jl/j. to 298 fx/j. 

 in length and the exposures were from one to one and a half hours. 

 In two of the experiments (Exps. 78 and 79) abiotic effects were indi- 

 <;ated by loss of corneal epithelium and characteristic changes in the 



