41 
of drawing conclusions from these data is indicated in the 
paragraph on Statistics, p. 226. They afford a complete and 
approximately correct picture of the distribution of the 
qualities tested, and not merely general averages. 
No. XVII.—THE SENSES. 
Sight and hearing are generally supposed to be more acute 
in persons belonging to tribes who have long dwelt in open 
countries and led a nomadic or insecure life. Myopia (short 
sight) is thought to be extremely rare among savages, who 
exercise the eye very little on minute objects, while their 
smell is more acute than fastidious. But exact data on these 
subjects are wanting. 
(a.) Sight. 
For testing clearness of vision, the test-dots employed 
for testing the sight of recruits in the British Army (see 
Pi. V), and the directions for using them by Prof. Long- 
more, may be useful— 
Each test-dot is i-inch square, and corresponds at a 
distance of 15 feet with a buliVeye 2 feet square at 600 
yards, which must be distinctly seen by every acceptable 
recruit. 
With perfectly acute vision these test-dots ought to be 
clearly visible in full daylight at 19 yards. 
Directions for using the Test-dots . 
1. Measure off 15 feet with precision. 
2. Hold the test-dot card or paper perfectly upright in 
front of the man, and let it face the light so as to he fully 
illuminated. 
