BRADLEY M. PATTEN 441 



Reaction Measurements. 



In all the tests with partially blinded animals, great care was used 

 to reproduce the experimental conditions under which the corre- 

 sponding tests on normal animals had been made. The method of 

 handhng the animals and the methods of measuring and tabulating 

 the reactions were the same as those described for normal animals (1). 

 The details have, therefore, been omitted and the data presented only 

 in the form of tabular and graphic summaries. 



For convenience in presentation and consideration, the reaction 

 measurements have been collected in three groups: (1) The reactions 

 to balanced opposed illumination of animals subjected to asymmetri- 

 cal interference with the photoreceptive mechanism. (2) The reac- 

 tions to balanced opposed illumination of animals subjected to sym- 

 metrical interference with the photoreceptive mechanism. (3) The 

 reactions to lateral and to anterior illumination of animals subjected 

 to symmetrical interference with the photoreceptive mechanism. 



Reactions to Balanced Opposed Illumination of Animals Subjected to 

 Asymmetrical Interference with the Photoreceptive Mechanism. 



In all the experiments on asymmetrical interference, the blackening 

 was carried out on the right side in one-half of the animals, and on 

 the left side in the other half of the individuals used. Tables I and 



II show the results of measurements made on animals with one lat- 

 eral eye group capped, and on animals with one side of the cephalo- 

 thorax blackened. These tables are given in detail partly as illus- 

 trations of the method of handling the measurements, but especially 

 to show the consistency and the range of individual variability en- 

 countered in typical series of measurements. Qualitatively there can 

 be no doubt as to the significance of the reactions. The approximate 

 consistency of the individual reactions would indicate that averages 

 obtained from the ten trials of an animal express with reasonable 

 quantitative accuracy the value of the reaction. 



In the case of the other series of measurements detailed tables have 

 been omitted and only the summary of the results presented. Table 



III summarizes the measurements made under balanced illumination, 

 on anim.als subjected to asymmetrical interference with the photo- 

 receptors. 



