There are various instances of symbolism in The South. The first symbol that is brought out clearly is the sky. The image of the darkening sky can be used to symbolize the slow nature that his reality was fading away and getting lost (Rodríguez-Monegal, 1973).
Thing started becoming less real. When Dahlmann got his first needle injection, he remembers all the fine details but soon as the medicine starts taking effect, he loses the fine details.
Just as the sky starts becoming dark, his memory starts becoming dark too. The store can also be used as symbolism. The store at first had a scarlet color that could symbolize violence. The store, however, loses the former violent color.
The loss of the violent scarlet color can be used to signify the loss of the protagonist's willingness to fight. The shopkeeper in the story can be used as a symbol. The protagonist, Dahlmann could recognize the shopkeeper, and even the shopkeeper knew his name. The presence of the shopkeeper reminded Dahlmann of the man from the sanitarium.
This shopkeeper can, therefore, be used as a symbol to show how Dahlmann is using the final images that he saw, before he had his dream, to make the vision seem real (Borges, 1944).
The title, "The South" can also be used as a symbol to symbolize Buenos Aires where both the author and the character were from. The use of the quote, "it was instinct" symbolizes the fact that growth in poor neighborhoods makes one have a form of hood instinct, especially when it comes to danger (Borges, 1944).
References
Borges, J. L. (1944). The South. Collected Fictions, 174-179.
Rodríguez-Monegal, E. (1973). Symbols in Borges' work. Modern Fiction Studies, 19(3), 325