351 



SCIENTIFIC SIDE-LIGHTS 



intellect 

 ntelligence 



ments of flint implements ; and at the present 

 time it [Brandon] is the only place in Eng- 

 land where gun-flints are still made. For 

 this purpose one particular layer of flint is 

 found to be peculiarly well adapted, on ac- 

 count of its hardness and fineness of grain, 

 while another layer, less suitable for gun- 

 flints, is known as " wall-stone," being much 

 used for building purposes. Now it is in- 

 teresting to find that even in very early 

 times the merits of the gun-flint layer were 

 well known and appreciated; for altho there 

 is abundance of flint on the surface the 

 ancient flint-men sank their shafts down 

 past the layer of " wall-stone," which oc- 

 curs at a depth of 19% feet, to the gun-flint 

 layer, which at the spot in question is 39 

 feet deep. AVEBURY Prehistoric Times, ch. 

 4, p. 78. (A., 1900.) 



1718. INTELLIGENCE IN LOWER 

 FORMS OF LIFE Worms Show Method in 

 Plugging Up Their Burrows Difficulty of 

 Drawing Dividing Line between the Intelli- 

 gent and the Automatic. If we consider 

 the cases [specified] we can hardly escape 

 from the conclusion that worms show some 

 degree of intelligence in their manner of 

 plugging up their burrows. Each particular 

 object is seized in too uniform a manner, 

 and from causes which we can generally 

 understand, for the result to be attributed 

 to mere chance. That every object has not 

 been drawn in by its pointed end may be 

 accounted for by labor having been saved 

 through some being inserted by their broader 

 or thicker ends. No doubt worms are led 

 by instinct to plug up their burrows; and 

 it might have been expected that they would 

 have been led by instinct how best to act 

 in each particular case, independently of in- 

 telligence. We see how difficult it is to judge 

 whether intelligence comes into play, for 

 even plants might sometimes be thought 

 to be thus directed; for instance, when dis- 

 placed leaves redirect their upper surfaces 

 towards the light by extremely complicated 

 movements and by the shortest course. With 

 animals actions appearing due to intelli- 

 gence may be performed through inherited 

 habit without any intelligence, altho aborigi- 

 nally thus acquired. Or the habit may have 

 been acquired through the preservation and 

 inheritance of beneficial variations of some 

 other habit; and in this case the new habit 

 will have been acquired independently of 

 intelligence throughout the whole course of 

 its development. There is no a priori im- 

 probability in worms having acquired special 

 instincts through either of these two latter 

 means. Nevertheless, it is incredible that 

 instincts should have been developed in ref- 

 erence to objects, such as the leaves or peti- 

 oles of foreign plants, wholly unknown to 

 the progenitors of the worms which act in 

 the described manner. Nor are their actions 

 so unvarying or inevitable as are most true 

 instincts. DARWIN The Formation of Vege- 

 table Mould, ch. 2, p. 26. (Hum., 1887.) 



1719. INTELLIGENCE OF ANIMALS 



Known to Man Only by Inference. By 

 mind we may mean two very different things,, 

 according as we contemplate it in our own 

 individual selves or in other organisms. For 

 if we contemplate our own mind we have 

 an immediate cognizance of a certain flow 

 of thoughts or feelings, which are the most 

 ultimate things, and indeed the only things, 

 of which we are cognizant. But if we con- 

 template mind in other persons or organisms, 

 we have no such immediate cognizance of 

 thoughts or feelings. In such cases we can. 

 only infer the existence and the nature of 

 thoughts and feelings from the activities 

 of the organisms which appear to exhibit 

 them. . . . All our knowledge of their 

 operations is derived, as it were, through 

 the medium of ambassadors, these ambassa- 

 dors being the activities of the organism. 

 Hence it is evident that in our study of ani- 

 mal intelligence we are wholly restricted 

 to the objective method. Starting from what 

 I know subjectively of the operations of my 

 own individual mind and the activities 

 which in my own organism they prompt, I 

 proceed by analogy to infer from the ob- 

 servable activities of other organisms what 

 are the mental operations that underlie 

 them. ROMANES Animal Intelligence, int., 

 p. 1. (A., 1899.) 



17 2O. limitations of 



Ceaseless Surprise of the Casarita Vain 

 Toil without Understanding. Another and 

 smaller species of Furnarius (F. cunicu- 

 larius) resembles the oven-bird in the gen- 

 eral reddish tint of its plumage, in a pe- 

 culiar shrill reiterated cry, and in an odd 

 manner of running by starts. From its af- 

 finity, the Spaniards call it " casarita " (or 

 little house-builder). . . . The casarita 

 builds its nest at the bottom of a narrow 

 cylindrical hole, which is said to extend 

 horizontally to nearly six feet underground. 

 Several of the country people told me that 

 when boys they had attempted to dig out 

 the nest, but had scarcely ever succeeded in 

 getting to the end of the passage. The 

 bird chooses any low bank of firm sandy soil 

 by the side of a road or stream. Here (at 

 Bahia Blanca) the walls round the houses 

 are built of hardened mud; and I noticed 

 that one, which enclosed a courtyard where 

 I lodged, was bored through by round holes 

 in a score of places. On asking the owner 

 the cause of this he bitterly complained 

 of the little casarita, several of which I 

 afterwards observed at work. It is rather 

 curious to find how incapable these birds 

 must be of acquiring any notion of thickness, 

 for altho they were constantly flitting over 

 the low wall they continued vainly to bore 

 through it, thinking it an excellent bank 

 for their nests. I do not doubt that each > 

 bird, as often as it came to daylight on the 

 opposite side, was greatly surprised at the 

 marvelous fact. DARWIN Naturalist's Voy- 

 age around the World,ch.5,p.95. (A., 1898.) 



