Both times it symbolizes something important to the plot; this represents the breakdown of the family. The first time, the menagerie was broken up because of the fight Tom and Amanda were having and the bad blood that was building because of it. The second was when Jim was driving Laura. The family was being broken up as a fight between Amanda and Tom was quick to break up the menagerie and since Jim broke the figure it foreshadowed the fight regarding Jim being engaged. This led to Tom leaving shortly after. The breaking of the glass also symbolizes the shattering of Tom and Laura's dreams. The first breakup was the foreshadowing of Tom's travel dream because it shows the bond he has with his sister. It was obvious that the relationship was too strong for Tom to leave without regretting it. The second was obviously Laura learning about Jim and being disappointed. Amanda's dreams are shattered every time since her dream is to make her children happy even though she tries to achieve it by living to the end.