In 1845, 5335 piles were driven into the foundation of the fort, the spaces between them filled with concrete, and the walls constructed from brick. This was the first multi-tiered fort in the Kronstadt fortress, equipped with powerful coastal defense weapons and capable of housing up to 1000 people. At the end of the 19th century, the third bubonic plague pandemic broke out. A "Special Laboratory" for vaccine production was established in the fort. On the first floor: a serum department, stables, and facilities for laboratory animals. On the second floor: an experimental laboratory, a vaccine department, and living quarters for the doctors. Here, 20 epidemiologists lived. Communication with the fort was carried out by a small steamboat called "Microbe". This was the third such laboratory in the world, with others in France and India. The resulting vaccine was supplied not only throughout Russia but also abroad.