A WONDERFITL ANIMAL. 91 



Xo other animal probably depends so much on the sense of sight 

 as we do, yet the eye is remarkably defective, not only in respect 

 of distance, but in its power of quantitative estimate. If we are 

 accustomed to take sugar in our tea or coffee, our sense of taste 

 will inform us at once whether our cup has been sweetened with 

 one, two, or three lumps. So, when the conductor of an omnibus 

 gives us change out of sixpence, we can guess pretty correctly 

 without looking whether he has made a mistake of a penny 

 (especially if it should be a penny short), simply by the weight 

 of the coppers. Yet it is exceedingly difficult to say whether a 

 room is lighted by one, two, or three candles, if the candles them- 

 selves be not seen ; moreover, the illumination of twenty candles 

 is scarcely to be differentiated from that of ten, when they are 

 hidden from ^-iew, and even the sudden addition of ten candles 

 to a like number already lighted fails to produce an impression 

 of the increase of more than two or three. It would be quite 

 possible to lower the lights in this room to one half of the volume 

 which they are now yielding without any perceptible alteration 

 to the majority of those present, provided the diminution were 

 effected gradually. Even the tactile perception is more delicate 

 and acute than this : in selecting one from a number of instru- 

 ments of the same shape but of different sizes (different in calibre, 

 that is to say), I find that my sense of touch is a much more 

 trustworthy guide than is the eye where the gradations are very 

 fine. The sight of savages, about which so much nonsense 

 has been talked, is by no means exceptionally acute, though 

 specialized in certain directions by habitude ; they may pick out, 

 for instance, a motionless animal which is invisible to the un- 

 practised eye, but my fellows in Nicaragua had the greatest 

 difficulty in seeing any distinction between an n and an m printed 

 in small type, and even between a full stop and a comma, thiugs 

 that strike us like a blow when one is misplaced for the other. 

 A child's vision appears to be deficient in comprehension rather 

 than intensity, though whether this is due to immaturity of the 

 organs involved or to defective receptivity of the centrum I am 

 unable to say. I was much impressed with this fact on one 

 occasion some few years ago, in taking a child of five and his 

 nurse — specimens again from my own vivarium — to the Crystal 

 Palace. Neither of them had been there before ; and when we 

 emerged fi-om the Low Level Station into the grounds, the nurse, 

 a girl of eighteen or twenty, was rapt in amazement at the 

 panorama which suddenly burst upon her, the enormous gardens, 

 the fountains, the wide terraces, and, behind all, the huge building 



