140 
E. M. CAMPBELL—ON INSTINCT. 
The annual report on the “ Migration of Birds ” is steadily 
increasing our knowledge of the facts connected with, the whole 
subject, and we may find that many phenomena, for which 
explanations are now sought, are mere accidental results. It is 
hardly necessary to state that the return of birds to their old nests 
cannot be taken as evidence of their possessing a “ sense of 
direction,” for, having been there before, they may be guided by 
landmarks, within sight of which their migratory course may have 
taken them. 
General Remarks. 
All analysis requires as a preliminary the most careful elimination 
of any accidental relation of the subject under examination. In no 
enquiry is this more important than one dealing with psychical 
phenomena, which frequently from their very nature are associated 
with more or less glamour, or endued with it by the observer. 
Butterflies often visit the droppings of birds, and a spider in Sumatra 
and Java (Ornithoscatoides decipiens, .Forbes) spins “a thin white 
web on the surface of a leaf, by means of which it secures itself on 
its back to the leaf, leaving its legs free to enclose and seize any 
insect unwittingly resting upon or crossing it.” * The web with 
the spider has all the appearance of recently-left birds’ excreta. 
Now it is impossible to think that the imitation is intentional, but 
it is the imitation which causes our admiration. It is reasonable 
to believe that the spider which originally made this web did so 
just as other spiders or caterpillars spin threads for their protection. 
Rood was thus obtained, so that there was no cause for making 
another snare. The practice was transmitted to posterity, and 
natural selection not only increased the resemblance of the snare, 
but probably also modified the colour of the spider, which, in the 
attitude described, completes the deception. Or again, the tom-tit 
may attract attention as it taps with its beak at the entrance of a 
hive,f and seizes the angry bee which comes out. But a wood¬ 
pecker will receive but a passing glance as he taps a loose piece of 
bark, and picks up the scared insects, which are leaving their pro¬ 
tection. 
One great source of error in estimating the intelligence of domestic 
animals, and more especially that of dogs, is in considering that the 
information we derive from their actions is always intended to be 
couveyed to us, as is undoubtedly sometimes the case. A son of a 
friend of mine visited a farmer just as he was starting on a poaching- 
expedition, and joined him out of love of adventure. The net was 
placed at one side of a copse, and the dog began to beat the game 
towards it, but he shortly returned and declined to leave his master, 
in spite of threats and blows. It was ultimately suggested that 
* See “ On the habits of Thomisus decipiens by H. 0. Forbes ; ‘Proc. Zool. 
Soc.,’ 1883, p. 586 ; and also “ On two new genera of Spiders,” by 0. P. Cam¬ 
bridge ; ‘Proc. Zool. Soc.,’ 1884, p. 196. 
f Some people about here call the tom-tit “ Take-a-bee ”—a term which is 
possibly as much due to the bird’s note as to the above occasional practice, which 
unfortunately I have not seen myself. 
