The first is on page 117.  The pap of life comes to mind.  "Out of the corner of his eye Gatsby saw that the blocks of the sidewalk really formed a ladder and mounted to a secret place above the trees--he could climb to it, if he climbed alone, and once there he could such on the pap of life, gulp down the incomparable milk of wonder."  The pap of life symbolizes wonder.  Just like there is wonder about Gatsby's island that is described as a fresh, green breast of the new world.

      The second page that relates to the passage is 144.  Page 144 is just the start though.  It ends with the accident.  This is the more negative description of the breast.  On page 145 Mrs. Wilson's breast is described.  "Michaelis and this man reached her first but when they had torn open her shirt waist still damp with perspiration they saw that her left breast was swinging loose like a flap and there was no need to listen for the heart beneath."