The emergence of antibiotic chemotherapy for tuberculosis within this period marks a departure from sanatorium-based management toward pharmacological disease control. The introduction of streptomycin as a practical cure for pulmonary tuberculosis, complemented by early work on para-aminosalicylic acid, catalyzed widespread adoption of combination drug regimens and standardized treatment protocols. Methodologies emphasized controlled clinical observations, in vivo bacterial enumeration, and studies of drug interactions that defined early chemotherapy paradigms and guided subsequent drug development. Historical Significance: This era established the antibiotic chemotherapy paradigm as the cornerstone of modern TB control, enabling rapid case-finding, standardized regimens, and global dissemination of treatment practices. Foundational insights into host–pathogen interactions, granuloma dynamics, and bacillary behavior under drug pressure informed later immunology, diagnostics, and vaccine strategies, while quantitative tissue-level models and metabolic differentiation studies shaped experimental therapy and drug assessment for decades.