Final answer:
Silver Nitrate is the bacteriostatic chemical that precipitates proteins and was used in newborns' eyes to prevent ophthalmia neonatorum.
Step-by-step explanation:
The chemical method that is bacteriostatic, interacts with proteins, can cause precipitation of cell proteins, and was historically used in newborns' eyes is d) Silver Nitrate. Silver nitrate acts as a bacteriostatic agent by binding with microbial proteins and inhibiting enzymatic activity, which leads to the denaturation of proteins.
Historically, a dilute solution of silver nitrate was applied to the eyes of newborns to prevent ophthalmia neonatorum, a form of conjunctivitis caused by Neisseria gonorrhoeae contracted during birth.