BALTIMORE (AP) -- The very travels that inspired Charles Darwin's theory of evolution and shaped modern biology may have led to one of the illnesses that plagued the British naturalist for decades and ultimately led to his death, modern researchers say.

   Darwin's ailments are the topic of an annual conference in Baltimore on Friday that offers modern medical diagnoses for the mysterious illnesses and deaths of historical figures. In past years, the conference hosted by the University of Maryland School of Medicine and Veterans Administration's Maryland Health Care System has looked at Alexander the Great, Wolfgang Amadeus Mozart and Booker T. Washington. Guest speakers include Darwin's great-great-granddaughter, poet Ruth Padel, who penned the book, ``Darwin: A Life in Poems.''

   Philip A. Mackowiak, the VA Maryland medical care clinical center chief and UM medical school professor who started the conference in 1995, had Darwin on his running list of possible candidates for years.

   Darwin, who lived from 1809 to 1882, traveled the world in his 20s cataloging and observing wildlife and later published ``On the Origin of Species.''

   Throughout his life, Darwin sought help for multiple health problems, which included vomiting stomach acids after every meal when the symptoms were at their worst. He was diagnosed with dozens of conditions including schizophrenia, appendicitis and lactose intolerance.

   ``It is particularly poignant that the scientists and physicians of his time could not provide Darwin, the father of modern life sciences, with relief from the ailments that affected so much of his life,'' Mackowiak said.

   The information used to evaluate Darwin's case came from several sources, Mackowiak said, including the naturalist's own letters, in which he wrote extensively about his complaints and his worries that he had passed on his illnesses to his children.

   Gastroenterologist Dr. Sidney Cohen, Thomas Jefferson University medical college professor of medicine and research director, assessed Darwin's ailments for the conference and identified three illnesses. Cohen, who had no X-rays or blood studies to use in his assessment, said he had only the documented symptoms: ``an analysis of this journey of invalidism that he suffered throughout his life.''

   ``It is a symptom-based specialty, though now we have some extraordinary diagnostic tools,'' he said. ``It would have been nice to have some CT scans.''

   Cohen concluded that Darwin suffered from cyclic vomiting syndrome early in his life. His weight and nutrition remained normal since he rarely vomited food, just stomach acid and other secretions.

   The gastroenterologist also believes Darwin contracted Chagas disease, a parasitic illness that can lie dormant for years, during a five-year trip around the globe on the HMS Beagle in his 20s. The hypothesis has been advanced in the past. That illness would describe the heart disease that beset Darwin later in life and eventually caused his death, Cohen said.

   He believes Darwin also suffered from Helicobacter pylori, the bacteria that cause peptic ulcer disease and often occurs with Chagas.

   Cohen's research into Darwin's ailments gave him a deeper appreciation for Darwin and the impact of his scientific work, despite his ailments.

   ``It's hard to know how it affected his work,'' Mackowiak said. ``But his productivity never waned.''