Note 11 — Chapter II · Animal Intelligence; an Experimental Study of the Associative Processes in Animals[4] (continued 2)
Reading edition
The back of the pen adjoined the elevator shaft, being separated from it by a partition 33 inches high. No. 2 heard the elevator coming up and put his paws up on the top of this partition so as to look over. In so doing he knocked the fastening of the cord at that end and opened the door. He did not turn to come out, and I shut the door again.