Herrera described various chemical procedures that give us an insight into the practice of science in the capital city, as well as the variety of methodologies common among physicians and pharmacists from France and Mexico, their doubts about certain results and attempts to explain them, the interactions they had with colleagues through the School of Medicine and the SMM, and the specialized bibliography circulating and being consulted in the Second Empire.
Herrera describió diversos procedimientos químicos que permiten adentrarse en la materialidad de la ciencia capitalina, así como a la diversidad de metodologías comunes entre médicos y farmacéuticos de Francia y México, a las dudas sobre ciertos resultados y los intentos de explicarlas, al contacto entre colegas a través de la Escuela de Medicina y la SMM, y la consulta de bibliografía especializada que circulaba en el Segundo Imperio.