During his sojourn in Paris Jacobson devoted a great deal of time to the study of practical medicine and surgery, and was so successful that the Danish government, on his return in 1813, obtained for him admission into the French army in order that he might study the medical system employed therein. In 1814 he served in a field-hospital near Leipzig, and became dangerously ill with fever when the lazaretto was attacked and pillaged by Cossacks. He returned to Denmark the same year (1814) and received from the University of Kiel an honorary diploma as doctor of medicine and surgery. In 1816 the same university conferred upon him the title of professor.
