142 INTELLIGENT BEHAVIOUR 
inches apart. On his return the stick caught at the ends. I 
whistled and turned as if to leave; and the dog pushed and 
struggled vigorously. He then retired into the field, lay down, 
and began gnawing the stick, but, when called, came slowly up 
to the railings and stuck again. After some efforts he put his 
head on one side, and brought the stick, a short one, through. 
After patting and encouraging him, I sent him after it again. 
On his return he came up to the railings with more confidence, 
but, holding the stick by the middle, found his passage barred. 
After some struggles he dropped it and came through without 
it. Sent after it again, he put his head through the railings, 
seized the stick by the middle, and then pulled with all his 
might, dancing up and down in his endeavours to effect a 
passage. Turning his head in his efforts, he at last brought 
the stick through. A third time he was again foiled; again 
dropped the stick ; and again seizing it by the middle tried to pull 
it through. I then placed the stick so that he could easily seize 
it by one end and draw it through the opening between the 
rails. But when I sent him after it, he went through into the 
field, picked up the stick by the middle, and tried to push his 
way between the railings, succeeding, after many abortive 
attempts, by holding his head on one side. 
Subsequent trials on many occasions yielded similar results. 
But the following summer, when I resumed the experiments, I 
was able with some guidance to teach him to bring a long stick 
to the railings, drop it, and then draw the stick through by one 
end; though even then, if he had dropped it so that one end 
just caught a rail, he often failed, shaking his head vigorously, 
dropping the stick and seizing it again, and repeating this 
behaviour until it chanced to fall in a more favourable position. 
He did not apparently perceive that by gently moving the stick 
a little one way or other the difficulty could be simply overcome 
with little effort. Nor when given a crooked stick, which caught 
in a rail, did he show any sign of perceiving that by pushing the 
stick and freeing the crook he could pull the stick through. 
Each time the crook caught he pulled with all his strength, 
seizing the stick now at the end, now in the middle, and now 
