During those years Carrillo exclusively dedicated himself to research and teaching, until becoming Head (1939) of the Neurology and Neurosurgery Service in the Central Military Hospital. This post afforded him a deep acquaintance with the real situation of public health in Argentina, which like his own province reflected a state of neglect in much of the countryside. He became well informed on the clinical files of all young men examined for enrollment into military service, and became aware of the high prevalence of poverty-linked diseases (especially in recruits from the poorest provinces). He carried out statistical studies showing that the country only had 45% of the required hospital beds, and that these were moreover unevenly distributed.