Christian ran a printing shop which he sold in 1887 and the family moved to Argentina to work with a South American Banknote Company in Buenos Aires.
Karl, now Carlos, joined the Museum of La Plata which needed a photographic and printing assistant under Francisco P. Moreno.
From 1888 to 1891, Christian and Carl helped set up the press in the Museum that allowed Moreno to produce scientific publications with photolithographic illustrations.
Bruch made several collecting and documenting expeditions, on the Chile border in 1894 followed by trips to Paraguay, Santa Feco Chaco, the sierras of Córdoba, San Luis, Tandil and Ventana.
He sent duplicate specimens to other entomologists around the world, and he is honoured in about 380 species including the genera Brucheiser, Bruchiana, Bruchomyia, Bruchiola, Bruchopria, Bruchomymar, Bruchaphodius, Bruchia, and Carlobruchia.