 In Switzerland he married Varvara Alexandrovna Zaytseva, sister of Russian publicist Varfolomey Zaytsev (1842–1882).In 1871 during the Franco-Prussian War Jacobi served as a military doctor in the Army of the Vosges led by Giuseppe Garibaldi.His wife, Zaytseva-Jacobi also served in the Army of the Vosges as a medical nurse and later left popular memoirs "Among Garibaldians.