621 



SCIENTIFIC SIDE-LIGHTS 



Sensibility 



eyes. One who is red-blind would see the 

 vermilion black or a dark grayish yellow; 

 that also is the correct reaction for his pe- 

 culiar construction of eye. But he ought 

 to be aware that his eyes differ from those 

 of other human beings. In itself the one 

 sensation is neither more correct nor more 

 false than the other, altho the red-seeing 

 are in the majority. In fact, the red color 

 of vermilion only has existence in as far 

 as there are eyes constructed like the ma- 

 jority of eyes. It is absolutely as much a 

 characteristic of vermilion to be black, 

 namely, for the red-blind. The fact is, the 

 light reflected from vermilion is not to be 

 termed red per se; it is only red for eyes 

 of a peculiar form. ... It would seem 

 as if it were unnecessary to mention this, 

 and for that reason we are apt to forget it, 

 and to be deceived into believing that the 

 red is a characteristic belonging to vermil- 

 ion, or to the light reflected from it, wholly 

 independent of our organs of sight. It is 

 different when we assert that the waves 

 thrown back from vermilion have a certain 

 length. That is an assertion we can make 

 independent of the peculiar nature of our 

 eyes; it is wholly a question of the relations 

 between the substance and the different sys- 

 tems of the waves of ether. HELMHOLTZ 

 Eandbuch der physiologischen Optik, p. 589. 

 (Translated for Scientific Side-Lights. ) 



3O74. SENSES, KEENNESS OF, 

 AMONG RUDE TRIBES Wonderful Skill 

 and Judgment of Savage Hunter. The na- 

 tives of the Brazilian forests, to whom track- 

 ing game is the chief business of life, do it 

 with a skill that fills with wonder the white 

 men who have watched them. The Botocudo 

 hunter, gliding stealthily through the under- 

 wood, knows every habit and sign of bird 

 and beast; the remains of berries and pods 

 show him what creature has fed there; he 

 knows how high up an armadillo displaces 

 the leaves in passing, and so can distinguish 

 its track from the snake's or tortoise's, and 

 follow it to its burrow by the scratches 

 of its scaly armor on the mud. Even the 

 sense of smell of this savage hunter is keen 

 enough to help him in tracking. Hidden 

 behind the trunk of a tree, he can imitate 

 the cries of birds and beasts to bring them 

 within range of his deadly poisoned arrow, 

 and he will even entice the alligator by ma- 

 king her rough eggs grate together where 

 they lie under leaves on the river-bank. If 

 an ape he has shot high in the boughs of 

 some immense tree remains hanging by its 

 tail, he will go up after it by a hanging 

 creeper where no white man would climb. 

 At last, laden with game and useful forest 

 things, such as palm-fiber to make ham- 

 mocks, or fruit to brew liquor, he finds his 

 way back to his hut by the sun and the 

 lie of the ground, and the twigs that he bent 

 back for way-marks as he crept through the 

 thicket. TYLOR Anthropology, ch. 9, p. 207. 

 (A., 1899.) 



3O75. SENSES, RELATIVE ACUTE- 

 NESS OF Keenness of Scent among Arabs. 

 It is said that the Arabs of the Sahara can 

 recognize the smell of a fire thirty or forty 

 miles distant. CARPENTER Mental Physi- 

 ology, bk. i, ch. 3, p. 141. (A., 1900.) 



3O 7 6. Keenness of Scent 



among Indians. We are told by Humboldt 

 that the Peruvian Indians in the darkest 

 night can not merely perceive through their 

 scent the approach of a stranger whilst yet 

 far distant, but can say whether he is an 

 Indian, European, or negro. CARPENTER 

 Mental Physiology, bk. i, ch. 3, p. 141. (A., 

 1900.) 



3O77. Progress Accom- 

 panied by Decline Smell of First Impor- 

 tance to Lower Animals Little Used by 

 Man. In general, this lowest, most animal, 

 least intellectual of the sensations [smell] 

 is peculiarly baffling of all attempts to re- 

 duce it to terms of science. In the developed 

 and cultivated human species smell has 

 come to be, for the most part, of the nature 

 of an esthetical advantage or affliction, 

 rather than a means of accurate knowledge. 

 But in the lower and less cultivated phases 

 of animal life it, by the prompt and accu- 

 rate information it furnishes, serves as a 

 most important factor in the preservation, 

 propagation, and evolution of the individual 

 and of the species. LADD Psychology, ch. 6, 

 p. 100. (S., 1899.) 



3D 7 8. SENSES, TO EXTEND THEIR 

 RANGE ONE OF THE PROBLEMS OF 

 SCIENCE Telescope and Microscope. One 

 of the problems of science, on which scien- 

 tific progress mainly depends, is to help the 

 senses of man by carrying them into regions 

 which could never be attained without such 

 help. Thus we arm the eye with the tele- 

 scope when we want to sound the depths of 

 space, and with the microscope when we 

 want to explore motion and structure in 

 their infinitesimal dimensions. TYNDALL 

 Lectures on Light, lect. 1, p. 12. (A., 1898.) 



3D 7 9. SENSIBILITY CHANGEABLE 

 The World Enduring. There are facts 

 which make us believe that our sensibility 

 is altering all the time, so that the same 

 object cannot easily give us the same sen- 

 sation over again. The eye's sensibility to 

 light is at its maximum when the eye is first 

 exposed, and blunts itstlf with surprising 

 rapidity. A long night's sleep will make it 

 see things twice as brightly on wakening, 

 as simple rest by closure will make it see 

 them later in the day. We feel things dif- 

 ferently according as we are sleepy or 

 awake, hungry or full, fresh or tired; dif- 

 ferently at night and in the morning; dif- 

 ferently in summer and in winter; and, above 

 all things, differently in childhood, man- 

 hood, and old age. Yet we never doubt that 

 our feelings reveal the same world, with the 

 same sensible qualities and the same sensi- 

 ble things occupying it. JAMES Psychology, 

 vol. i, ch. 9, p. 232. (H. H. & Co., 1899.) 



