The symbol that is most apparent when the narrator talks of her memories of the convalescent home is one of distance between the parents and their children that they sent to the convalescent home, supposedly for their own good and benefit. The narrator paints a terrifying image of visiting days, with the children standing on balconies in smart clothing and the parents forced to shout up to them because they weren't allowed to get any closer:
The parents stand below shrieking up to be heard and the children shriek down to be heard, and between them the invisible wall "Not To Be Contaminated by Parental Germs or Physical Affection."
It is this "invisible wall" that is the governing symbol in the presentation of the convalescent home, as it exposes both the cruelty of medical thought at the time, which believed that "Physical Affection" was something that could "contaminate," but it also exposes the guilt that the mother feels for having sent her daughter there, and shows the invisible wall that has been erected between them as a result. The description of the convalescent home is a rather harrowing one, as the children are stripped of any kind of affection or love, and clearly suffer as a result.