48 COLOR SENSITIVITY OF THE PERIPHERAL RETINA. 



Each exploration was carried through with three different lumin- 

 osites of stimulus. Inasmuch, however, as the intermediate luminosity 

 revealed no characteristic features, we shall append only the data 

 obtained from the maximal and minimal stimuli. 



Before the exploration of the retina was begun the observers were 

 submitted to an examination in the naming of colors. Each was asked 

 to describe the colors corresponding to certain scale-readings in the 

 spectroscope and to state the position of the most characteristic tone of 

 each of the colors. As a result of this examination, a high degree of 

 uniformity in the employment of color names was attained. During 

 the course of the experiments the observers were asked to characterize 

 their color sensations as definitely as possible. Thus the observer who 

 reported a green sensation was required to state whether he saw a 

 characteristic green or a green which inclined toward yellow or toward 

 blue, whether it contained a small or a large admixture of yellow (or 

 blue), etc. Every precaution was taken to have the color sensations 

 described as accurately and as definitely as possible. 



C. GROSS RESULTS. 



Tables i, 2, 3, and 4 contain a general statement of the results 

 yielded by the experiments just described. Tables i and 2 give the 

 results obtained by means of the seven stimuli of relatively high inten- 

 sity, while the results tabulated in 3 and 4 were obtained with the same 

 color stimuli in lesser intensity. The results obtained in the explora- 

 tion of the nasal half of the horizontal meridian of the retina will be 

 found in Tables i and 3 ; those obtained from the temporal half of the 

 same meridian are given in Tables 2 and 4. 



The results as set down in the tables are grouped by stimuli ; thus, 

 the upper section of each table records the sensations reported by each 

 observer (B, G, J, P, and S) on the application of the red stimulus (R). 



The numbers in the table express the degree of eccentricity (in 

 degrees) of the stimulus, when each judgment was reported. The 

 colors reported are indicated by the initials (R, red ; O, orange ; etc.) , 

 excepting in case of slight saturation, where the color name with its 

 suffix is written out in full. Pairs of initials indicate judgments of 

 composite colors, the second letter referring to the stronger component ; 

 thus, OR means a red, containing a tinge of orange. In a few cases 

 the observer reported the presence of a color which was not sufficiently 

 distinct to be identified; judgments of this sort are indicated by a ques- 

 tion mark (?). The color-initial G always signifies green; when gray 

 is meant the name appears in full. 



