RT Journal A1 BEAN WB, FUNK D T1 THe vasculocardiac syndrome of metastatic carcinoid JF A.M.A. Archives of Internal Medicine JO A.M.A. Archives of Internal Medicine YR 1959 FD February 1 VO 103 IS 2 SP 189 OP 199 DO 10.1001/archinte.1959.00270020017003 UL http://dx.doi.org/10.1001/archinte.1959.00270020017003 AB In the last few years, serotonin has emerged as a fascinating natural humor of the human body. Its myriad, miscellaneous, and mystifying functions are the delight and confusion of pharmacologists, the fascination and mystery of internists and surgeons, and the hope and bewilderment of psychiatrists and psychologists, as well as a phantom and will-o'-the-wisp for hematologists. The first clue about what we now know as serotonin appeared, but hardly emerged, about 90 years ago when Ludwig demonstrated that blood which had been defibrinated contained a vasoconstrictor principle not demonstrable in the same blood before coagulation. While most of the attention on the clotting mechanism traditionally focused on what had been taken out of blood in the process of clotting, here was a paradoxical situation—something had been added. Rapport and Page sought this mysterious vasoconstrictor and identified it in 1948. Thus 80 years elapsed between the discovery of a biological principle,