San Telmo began to improve despite these challenges, particularly after Rosas' removal from power in 1852. The establishment of new clinics, the installation of gas mains, lighting, sewers, running water and cobblestones and the opening of the city's main wholesale market led to increasing interest in the area on the part of the well-to-do and numerous imposing homes were built in the western half of San Telmo. This promising era ended abruptly when an epidemic of yellow fever struck the area in 1871. The new clinics and the heroic efforts of physicians like Florentino Ameghino helped curb the northward spread of the epidemic; but as time went on it claimed over 10,000 lives, and this led to the exodus of San Telmo's growing middle and upper classes into what later became Barrio Norte.