Carrillo also produced a body of research into brain herniations protruding into blood cysterns (cysternal herniations) and the syndromes occurring after a brain contusion; he discovered what became known as "Carrillo's disease," or acute papillitis; described in detail the cerebral scleroses, during whose research he performed many cerebral transplants (brain grafts) between living rabbits; and histologically reclassified the cerebral tumors and the inflammations of the innermost brain envelope (arachnoid mater) known as arachnoiditis. He also proposed a widely used, pre-DSM classification of mental illnesses. Against considerable opposition from conservative colleagues, in 1942 and at the age of 36 Carrillo became the Chair of Neurosurgery at the University of Buenos Aires School of Medicine. Among the influential Argentine physicians he trained were Germán Dickmann, Raúl Matera, D. E. Nijensohn, Raúl Carrea, Fernando Knesevich, Lorenzo Amezúa, Jorge Cohen, Jacobo and Leon Zimman, Rogelio Driollet Laspiur, Juan C. Christensen, and Alberto D. Kaplan.