Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / The amount o serotonin, one of the biologically active amines, was determined in selected species of non-mammalian vertebrates - the dogfish Mustelus canis, the tautog Tautoga onitis, the turtle Pseudymys scripta elegans, and the chicken Gellus gallus. The extraction procedure employed was highly sensitive and specific. Contaminating indoles which occur naturally in tissues were removed before extraction by shaking with diethyl ether and adjusting the pH. Serotonin was then extracted with butanol from an alkaline, sodium chloride-saturated solution and re-extracted back into dilute acid. It was identified on a Farrand spectrophotofluorometer by its characteristic activation activation peak at 305 mu and fluorescence peak at 550 mu, and the amount present was determined. The range in chicken whole blood was found to be 10.3-19.4 ug. per ml. Under the conditions of the experiment, the major portion of chicken blood serotonin could not be shown to be contained in the thrombocytes. The range of serotonin in turtle whole blood was found to be .228-1.32 ug. per ml. Serotonin could not be demonstrated in the tautog or the dogfish. / 2031-01-01