She brought down thirteen more bubbles of air and then the house was filled with it. On the lower side of the open doorway there was water and on the upper side was air, and each stayed where it should. When Mrs. Spider came into her house, she always had some air caught in the hairs which covered her body, even when she did not bring a bubble of it in her hindlegs. She had to have plenty of it in her home to keep her from drowning, for she could not breathe water like a fish. "Side doors may be all right for Sticklebacks," said she, "for they do not need air, but I must have bottom doors, and I will have them too!"