The travels through Mexico were dangerous due to civil conflict following the Mexican-American War and the 1855 overthrow by the Liberal Party of President Antonio López de Santa Anna, which eventually led to the Reform War. As the expedition became more dangerous, and the war seemed to approach, Saussure became increasingly displeased with Mexico, reporting he wished he had chosen Ecuador instead. Saussure, Peyrot, and Grosjean cut the trip short and returned to Geneva in 1856 by way of the United States, taking the specimens with them. Sumichrast remained behind in Mexico.
