front of the box. As may be seen in the accompanying figure (Fig. 2), she opened the door in one of her first trials by
Fig. 2
The female English Sparrow (at the lower right hatid corner of the box) opening the door by one of her first accidental methods. Many efforts of other kinds preceded this.
crawling in between the wire and strings and accidentally pull- ing on string B with the back of her head. In Fig. 3 is shown a way of opening the door which is, if such is possible,
Fig. 3
The same English Sparrow as in Fig. 1 opening the door on the next day. She did not know what she had done until after she returned to the floor.
even more accidental. Here she is pushing down on string B with her head turned away from the door. She did not know