In his interest to specialize in urology and bacteriology, by the month of May, he returned to Spain and obtained his Doctorate in Medicine at the Faculty of Medicine of the University of Madrid. While doing his Doctorate, he attended the Central Laboratory of Histology, Bacteriology and Vaccination of Dr. Santiago Ramón y Cajal, doing bacteriological diagnosis of bubonic plague and the culture of its bacillus. At that time, a plague of bubonic plague spread in Lisbon, Portugal, and he was appointed as a volunteer observer in the Spanish Commission that traveled to this country.