Abstract: A method for analysing function of a biosystem (16) based on analysis of a sample (12) taken from a portion of said biosystem (18); said method comprising exposing said sample to incident energy (10) derived from an energy source (11); receiving radiated energy from said sample consequent to impingement of said incident energy on said sample; passing at least a portion of said radiated energy through a transducer (13) thereby to derive an information signal (15) which characterises an aspect of said sample (12); analysing said information signal to produce biosystem data which can be used to identify said aspect of said sample (12).