& in this state they are easily squashed. The great black bug of the Pampas is identified by Richard Keynes as Triatoma infestans, commonly called winchuka (vinchuca), the vector for Trypanosoma cruzi which leads to Chagas disease. It is unlikely that Darwin was infected on this occasion as he did not mention having a fever in the days following the incident, but it is possible that he could have been infected in September 1834 when he recorded being ill but made no note about being bitten by a Benchuca at that time. Arguments for the Chagas hypothesis were mainly his gastric symptoms and some of his nervous signs and symptoms (caused in Chagas by an imbalance of the autonomic nervous system), malaise and fatigue, as well as his ultimate cause of death, which seems to have been chronic cardiac failure (present in ca. 20% of Chagas patients, with cardiomegaly and ventricular tip aneurysm) accompanied by lung edema. Evidences against the Chagas hypothesis are numerous, however: Darwin died at a relatively old age for his time (73 years old); The symptoms abated as he aged, which is not typical for the disease, where age exacerbates the symptoms; He did not seem to have several of the pathological damages present at chronic Chagas disease, such as megacolon and megaesophagus; Some of the symptoms, such as tachycardia, fatigue and tremors, were already present before the Beagle voyage; The numerous partial exacerbations and remissions are unusual in Chagas disease; The incidence of trypanosome-infested benchucas in Mendoza, Argentina (which has a colder climate), where Darwin reported the bite, is very low; No other members of Beagle'''s crew who accompanied Darwin in his land trip showed signs of a similar disease; Recently, unsuccessful requests were made to test Darwin's remains for T. cruzi DNA at the Westminster Abbey by using modern PCR techniques but were met with a refusal by the Abbey's curator. The attempt was the subject of a recent documentary of Discovery Health Channel. Ménière's disease The hypothesis of Ménière's disease has gained some popularity. A diagnosis of Ménière's disease is based on a series of symptoms, some of which were present in Darwin's case, such as tinnitus, vertigo, dizziness, nausea, motion sickness, vomiting, continual malaise and fatigue. The fact that Darwin did not suffer from hearing loss, and that "fullness" of the ears is never mentioned, practically excludes Ménière's disease. The definition of