Johnsy is one of the "art people" who has migrated to Greenwich Village, New York, and as an artist, she is a sensitive young girl, both physically and psychologically.
Her illness and the doctor's comments illustrate these personality traits. When Johnsy, who has lived all her life in California and is not acclimated to cold weather, contracts pneumonia, she does not fare well because she has built no immunities nor does she have the spirit to fight for her life against this condition. When the doctor comes on a house call, as was done earlier in the twentieth century, he tells the friend and roommate, Sue,
"She has one chance in--let us say, ten....Your little lady has made up her mind that she's not going to get well. Has she anything on her mind?"
Sue replies that Johnsy is not depressed about a man or anything else. So, the doctor concludes that "it is the weakness then," implying that Johnsy's spirit is not strong and her will to live does not prevail over her spirit. Because of this weakness, Johnsy will die unless measures are taken by Sue to try to strengthen the will of Johnsy to fight for her life. With Behrman, Sue forms a plan to motivate Johnsy: If the ivy leaf outside in the brutal cold survives, Johnsy agrees that she will try to hold on. So, when she awakens one morning and sees that this leaf has held tenaciously to live, Johnsy is encouraged in spirit and derives strength from the idea that one can, indeed, overcome death through the spirit.