Domagk1 reported in his original communication on the use of the hydrochloride of 4 sulfamido-2', 4' diamino azo-benzene in the treatment of experimental streptococcic infections of mice that phagocytosis of the streptococci by the leukocytes played an important rôle in clearing the tissues of streptococci in the treated mice. Levaditi and Vaisman2 soon afterward advanced the hypothesis (without much experimental evidence) that this chemical interfered with capsule formation, thus rendering the streptococci susceptible to phagocytosis. The Tréfouëls and their associates3 made the important observation in 1935 that para-aminobenzenesulfonamide was active as a therapeutic agent in curing mice of experimental streptococcic infections. Fourneau and his collaborators4 first reported that para-aminobenzenesulfonamide had a bacteriostatic effect on the growth of certain molds.
Colebrook and Kenny5 stated that the hydrochloride of 4 sulfamido-2', 4' diamino azo-benzene and the disodium salt of 4 sulfamido-phenyl-2'-azo-7'-acetyl-amino-1'-hydroxynapthalene-3', 6'-disulfonic acid possessed practically no bacteriostatic
BLISS EA, LONG PH. OBSERVATIONS ON THE MODE OF ACTION OF SULFANILAMIDE. JAMA. 1937;109(19):1524-1528. doi:10.1001/jama.1937.02780450028008