Final answer:
Robert Koch identified the bacillus that causes Tuberculosis, which was a significant achievement in medical science and bacteriology.
Step-by-step explanation:
The man who first identified the bacillus that causes Tuberculosis was Robert Koch. Koch's groundbreaking work in bacteriology led to one of the greatest discoveries of modern science. He developed a set of criteria, known as Koch's postulates, to prove that a specific microbe causes a particular disease.
These postulates required that the organism be present in all cases of the disease, be isolated and grown in pure culture, and be able to reproduce the disease when introduced to a healthy host. Koch applied these postulates to several diseases, including tuberculosis, whereby he identified Mycobacterium tuberculosis as the causative agent.
Moreover, Koch's work advanced the methods of microbial staining and culture. His assistant, Julius Petri, contributed to this legacy by inventing the Petri dish, a mainstay in modern laboratories. The discovery of the M. tuberculosis bacillus has had a lasting impact on medicine, as this pathogen is a major cause of lung infection and poses significant challenges in treatment, especially with the emergence of multidrug-resistant strains.