Hitler's tremors and irregular heartbeat during the last years of his life could have been symptoms of tertiary syphilis. Along with another doctor, Morell diagnosed them as such by early 1945 in a joint report to Heinrich Himmler. Some historians have also cited Hitler's discussion of syphilis across fourteen pages of Mein Kampf, which he called a "Jewish disease", leading to speculation he may have had the disease himself, since it may be difficult to imagine another reason for such a tirade.
Since the 1870s, however, it was a common rhetorical practice on the völkisch right to associate Jews with diseases such as syphilis. Historian Robert Waite claims Hitler tested negative on a Wassermann test as late as 1939 although this does not prove that he did not have the disease as the Wasserman test was prone to false results. Regardless of whether he actually had syphilis or not, Hitler lived in constant fear of the disease and took treatment for it no matter what doctors told him.
In his biography of Dr Felix Kersten, called The Man with the Miraculous Hands, journalist and Académie française member Joseph Kessel wrote of how in the winter of 1942 Kersten heard of Hitler's medical condition. Consulted by his patient, Heinrich Himmler, as to whether he could "assist a man who suffers from severe headaches, dizziness and insomnia", Kersten was shown a top secret twenty-six page report. It detailed how Hitler had contracted syphilis in his youth and was treated for it at a hospital in Pasewalk, Germany. However in 1937 symptoms re-appeared, showing the disease was still active, and by the start of 1942 signs were evident that progressive syphilitic paralysis (Tabes dorsalis) was occurring. Himmler advised Kersten that Dr Theodore Morell was in charge of Hitler's treatment, and that it was a state secret. The book also relates how Kersten learnt from Himmler's secretary, Rudolf Brandt that, at that time, probably the only other people privy to the report's information were Martin Bormann and Hermann Göring.