circles contributed potently to Semmelweis' lack of recognition. Ede Flórián Birly, Semmelweis's predecessor as Professor of Obstetrics at the University of Pest, never accepted Semmelweis's teachings; he continued to believe that puerperal fever was due to uncleanliness of the bowel. August Breisky, an obstetrician in Prague, rejected Semmelweis's book as "naïve" and he referred to it as "the Koran of puerperal theology". Breisky objected that Semmelweis had not proved that puerperal fever and pyemia are identical, and he insisted that other factors beyond decaying organic matter certainly had to be included in the etiology of the disease. Carl Edvard Marius Levy, head of the Copenhagen maternity hospital and an outspoken critic of Semmelweis's ideas, had reservations concerning the unspecific nature of cadaverous particles and that the supposed quantities were unreasonably small. In fact, Robert Koch later used precisely this fact to prove that various infecting materials contained living organisms which could reproduce in the human body; that is, since the poison could be neither chemical nor physical in operation, it must be biological. It has been contended that Semmelweis could have had an even greater impact if he had managed to communicate his findings more effectively and avoid antagonising the medical establishment, even given the opposition from entrenched viewpoints. Breakdown and death After a number of unfavorable foreign reviews of his 1861 book, Semmelweis lashed out against his critics in a series of open letters. They were addressed to various prominent European obstetricians, including Späth, Scanzoni, Siebold, and to "all obstetricians". They were full of bitterness, desperation, and fury and were "highly polemical and superlatively offensive", at times denouncing his critics as irresponsible murderers or ignoramuses. He also called upon Siebold to arrange a meeting of German obstetricians somewhere in Germany to provide a forum for discussions on puerperal fever, where he would stay "until all have been converted to his theory." In mid-1865, his public behaviour became exasperating and embarrassing to his associates. He also began to drink immoderately; he spent progressively more time away from his family, sometimes in the company of a prostitute; and his wife noticed changes in his sexual behavior. On 13 July 1865, the Semmelweis family visited friends, and during the visit, Semmelweis's behavior seemed particularly inappropriate. Semmelweis's alleged affliction has been a subject of some debate. According to K. Codell Carter, in his biography of Semmelweis, its exact nature cannot be determined:It is